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ASHRAE Journal Podcast Episode 14

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Left, Garen Ewbank; Steve Hamstra

Are Ground-Source Heat Pumps Our Future?

“When we have something that works, we just tend to do that over and over again… we’re all liability averse, but there’s also a place, especially now, for us to consider new and emerging technologies,” says Steve Hamstra, P.E., HBDP, Member ASHRAE. Join Hamstra and Garen Ewbank, Member ASHRAE, as they discuss the implementation, reliability and resiliency of ground-source heat pumps; the cost, incentives and benefits of retrofitting with new technology; and why the future looks bright for the industry.

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  • Guest Bios

    Garen Ewbank, Member ASHRAE, is managing member of Ewbank Geo Testing, LLC, member of GeoAire International and a managing member for The GreyEdge Group, LLC. He has worked in the ground source heat pump (GSHP) industry since 1979 and has been involved in the design and implementation of well over 100,000 MW (millions of feet) of installed heat-pump-equivalent capacity in North America. He has been a contributor to several training courses, including the Certified GeoExchange Designer Course and Syllabus that has been adopted by the International Ground Source Heat Pump Association (IGSHPA) and the Association of Energy Engineers. He is a member of the technical committee to develop the Bi-National CSA/ANSI C448 Standard for the Design and Installation of Ground Source Heat Pumps for Commercial and Residential Buildings as well as a committee member for IAPMO on ambient temperature loops. He developed the in situ thermal conductivity testing methodology used by the GSHP industry to size and design ground heat exchangers (GHEXs). Additionally, he has been a primary investigator/collaborator on numerous applied research projects on GHEXs, borehole resistance and thermal storage and has peer reviewed several software applications to size and design GHEXs. He is co-owner of the patented Advanced Thermal Conductivity Method (ATCM) that shortens the testing duration and quantifies the diffusivity.

    Steve Hamstra, P.E., HBDP, Member ASHRAE, has committed most of his 40+ years of professional engineering practice to the design of high-performance buildings. His focus areas include ground-source heat pumps (he chairs ASHRAE TC 6.8, Geothermal Heat Pump and Energy Recovery Applications), ambient temperature loop district thermal systems, wastewater energy transfer and other energy-saving technologies. He is an ASHRAE HBDP, has served as an ASHRAE Distinguished Lecturer, received an ASHRAE Global Technology Award in 2014 and is also an Association of Energy Engineers Fellow. He currently directs a U.S. DOE-funded R&D project at Melink ZERO focused on thermal energy storage batteries, and he is also a managing member of The GreyEdge Group, a consortium focused on large-scale community energy systems. He holds several patents and is an advisor to several companies.

  • Transcription
    ASHRAE Journal:
    ASHRAE Journal presents.

    Steve Hamstra:
    Sometimes in our industry when we have something that works, we just tend to do that over and over again, which there's nothing wrong with that. We're all liability averse, but there's also a place, especially now, for us to consider new and emerging technologies, and can we safely apply them for our clients, and how do we then measure the benefits over time?

    ASHRAE Journal:
    Episode 14: Steve Hamstra and Garen Ewbank discuss the implementation, reliability, and resiliency of ground-source heat pumps; the cost, incentives, and benefits of retrofitting with new technology; and why the future looks bright for the industry.

    Steve Hamstra:
    Hello, I'm Steve Hamstra, the outgoing chair of ASHRAE's Ground Source Heat Pump Technical Committee 6.8. I'm also vice president of engineering for Melink Zero in Ohio, and managing member of The GreyEdge Group, a board member of a new startup with heat pump technology, Next Temp Solutions, a certified geo exchange designer, an AEE fellow, and an ASHRAE high performance design professional.

    Garen Ewbank:
    Thank you, Steve I'm Garen Ewbank. I have a BS in industrial engineering and management from Oklahoma State University, full member of ASHRAE and Technical Committee 6.8, I'm a corresponding member. I'm a fellow, a legend in energy, and I hold six certifications with the Association of Energy Engineers, including the certified energy manager, carbon auditing professional, and the certified geo exchange designer. I'm a managing member of the TGE Group, which is The GreyEdge Group. All right?

    I'm the owner of Ewbank Geo Testing. I'm a co-patent holder for the advanced thermal connectivity testing methods, which quantifies the volumetric heat capacity by direct measurements, which is new to our industry, and I've been the principal investigator on a number of ground heat exchanger research projects.

    Steve Hamstra:
    Well, when we're recording this, we've just completed ASHRAE's annual summer meeting in Toronto, and at that meeting, the board of directors of ASHRAE met and issued a statement for the society focused on decarbonization and resiliency. The bottom line for society members and practitioners is that all of us have responsibilities to deal with a reduction in carbon emissions globally, and also to think about the impact of climate change on our design, and how that in some cases reduces equipment capacity being when it's really, really hot or really, really cold, and Garen and I will be touching on resiliency and ground source heat pumps some more as we move on.

    One of the issues that often comes up with the discussion of electrification is how is this going to impact our electrical grid? Can we support all these efforts to have electric cars, non-fossil fuel boilers, instead shifting to heat pumps, et cetera. Indeed, we're seeing portions of the US, East Coast, West Coast seeking to either limit new natural gas distribution system expansions or even have told certain companies, gas companies, they cannot replace aging, natural gas mains, and they need to find other ways to provide heating and cooling, et cetera. And we seek a lot of this activity in New York, and California, and Oregon, and in other states.

    A lot of the challenge as we alluded to earlier, has to do with resiliency, and how certain forms of heat pumps may or may not perform well when you really need them the most. Garen and I are involved with a lot of initiatives up in New England, and they've really identified that the application of air source heat pumps, which uses the atmospheric air as a heat source or a heat sink, can compound problems, and even a relatively small market penetration of say 15% air source heat pumps into the marketplace would tend to shift summer electrical demand to the winter months, and would create a kind of a maxed out grid circumstance. So air source heat pumps by themselves are not the full answer.

    Garen Ewbank:
    Well, ground source heat pumps, and when we talk about these, we want to talk about their efficiency, and they gain their efficiency because their sink and source is coming from the ground heat exchanger, which modifies or moderates the temperature that the heat pump is going to use for its lift for the refrigerant. So they become very efficient year round. With that being said then, we don't get the big demand increases that we would see with an air source heat pump. So we're moderating that to a large extent and able to maintain the comfort and the space for all the people there.

    The weather events is kind of interesting. A couple of years ago, one of my partners was in Australia, and they were having a terrible heat wave. It was January, and the grids were going down. They were having a terrible time. At the same time, another associate of mine was in Indiana, and he sent me a picture of the controls for his heat pump, and it said as it was -16 out, when going 30 mile an hour, that his heat pump thought it was 46 degrees out. It was cranking right on and along.

    Steve Hamstra:
    We've been doing a lot of research, and a lot of this is being led by Department of Energy and Oak Ridge National Labs, and also the application of thermal energy storage with ground source heat pump systems. And we've demonstrated that we can reduce the size of the earth heat exchanger if we apply the appropriate types of thermal energy storage, but maybe, Garen, you could hit on this resiliency conversation a little bit.

    Garen Ewbank:
    Surely. When we talk about resiliency and reliability, there are two areas we really have to talk about, and later, I'm going to talk a little bit about energy at risk for a facility, but the reliability of these systems is ground heat exchangers out in the ground, and all it does is circulate a fluid, mainly water or water with an antifreeze, through it, and so it's very reliable. As long as the pump is running, this thing will go, absolutely. The resiliency is that we're coupled to the deep earth temperatures, and when we do that, that allows us then to get away from the extremes of that outside air as we're going through it.

    So that resiliency then travels all the way through the grid that they're powering these devices with, which now brings us into how do we handle beneficial electrification? Well, when we go down that road, we understand that we can't giantly change the demands left, or right, or up, or down, or whatever, but a little bit of usage, say a CoP of five on a unit, would give us five units out for one unit purchased. Then you can see how reliable and resilient these systems can be along with their increased efficiency.

    There is not much to damage these ground heat exchangers. All right? If you marked them well, keep the backhoe out of there, they're going to last a very long time, and I've never seen a ground heat exchanger hauled off in the back of a truck by somebody stealing it. It's going to be kind of hard to do, so they're not susceptible to that damage. The earth coupling, what it does is moderate the temperature swings that the air source heat pumps deal with with the outside air, and so that puts much less strain and stress on the HVAC equipment, which says it's going to last considerably longer, because we have lower lifts through that refrigerant circuit.

    Steve Hamstra:
    Building on that theme of resiliency, I'm reminded of a story that was published in the ASHRAE Journal some years ago. It was about a hotel on the Atlantic coast of Florida, and the area got hit hard by the hurricane, and almost every facility along that coast in that area was taken totally offline. Their air cooled condensing units for the air conditioning were either damaged or taken out in the storm, whereas this hotel had all of its infrastructure basically underground or inside. And so they were actually able to get the hotel back online and serve as a place of refuge for those folks that were displaced, and I think that speaks to the resiliency that we're going to find this more and more important as we see, unfortunately, more and more climate related events that seem to push things hotter or colder, depending on the time of year.

    Garen Ewbank:
    I've got an interesting story also. In 2011, we're doing an applied research project at the Habitat for Humanity in northern Oklahoma City, Southern Edmond, but anyway, we were in the site, and it was April, and we all had our smartphones going. And we could see that there was a tornado headed to the little town of Goldsby, Oklahoma. A number of the people there had their kids in that daycare facility. We had a little time, so I told them, "Hey, you guys get out of here, get those kids safe. Okay?"

    They did. Their children were removed, but some of the kids, their parents couldn't pick them up. The facility had an underground storm shelter in the garage. The remaining kids were all in there underground. The tornado came through, completely leveled that facility all the way down to the slab, the heat pump that was doing the heating and cooling ended up a quarter of a mile away in the tree row, and the insurance company to rebuild it said, "Well, you got to remove the slab and get going again." And they did. They reconnected to the existing ground heat exchanger and went back to working. So much like the kids were saved, so was that ground heat exchanger.

    Steve Hamstra:
    Great story, Garen. Well, one of the conversations that we have a lot is, "Oh man, these ground source heat pump systems, they just cost too much." Whenever I hear that, I encourage people to think about all the costs, whether this is new construction or retrofit. It's not just the first cost, but if it's new construction, what's the cost to actually run a fossil gas main to that facility? Depending on where you're at in the world, this can cost from 35,000 to I've heard over 100,000 when you include all the costs of the mains and the pressurization station.

    So not all of that is born immediately by the building owner, but it has to be amortized over time. So that is a cost. So think about what your cost would be or society's cost would be if there was no fossil gas connection. As we look at the application of air source heat pumps, as we've mentioned before, their capacity is impacted by the temperature of the air. So as that air gets really hot, their efficiency and capacity goes down to cool, and conversely, when it's really cold, their ability to heat.

    That may mean you need to have a larger electrical service to handle that additional electrical load than we would say with a ground source heat pump system. So that's something else to consider. Next, lifespan. ASHRAE has indicated on an average air source heat pumps probably in the 15 to 17 year category, whereas water source or ground source heat pumps more like 25+. So we're talking 50% to 60% longer life for the ground couple system than the air source system.

    And as Garen shared in that example of the storm, when that heat pump is worn out, the pipe in the ground isn't worn out. That's going to go through multiple heat pump cycles and as technology changes and improves over time, but that big investment in the ground will continue to support that equipment into the future.

    Garen Ewbank:
    Yeah, that's a good point, Steve, because when we get into this, you're going to find that we really do have less expense for maintenance with ground source heat pumps. That noisy condenser that might be out if you ever have gone up to a large group of apartments or something like that, it's noisy. All right? With everything packed together and close, but that ground heat exchanger is just simply a convective circulation circuit, and all it does is move water. All right?

    You don't hear it. You don't see it. You don't know it's there. And that's where we get a really long life. So the inside equipment has less stress on the unit, because we're moderating that refrigerant lift, making it run a little bit more efficiently and a lot happier. And the whole idea of designing a ground heat exchanger is to keep those heat pumps happy and running good.

    Steve Hamstra:
    Excellent point. Garen and I are working in a lot of different marketplaces, and one of the things that we're seeing globally is the rise of the carbon tax. For example, our neighbors to the north, Canada, they've recently instituted carbon tax, and what it is it's, if you will, a tax penalty that is tied to your emissions. And so as time goes on, that carbon tax will increase and it's $50 a ton now, and it'll be $150 a ton of carbon, I think, in around five years.

    But my point there is if you haven't over a period of time driven your building to a net-zero carbon operating mode, you're going to start seeing in some places a penalty on your taxes, and that hasn't happened here in the states, but it's certainly been talked about a lot, and that can tend to incentivize a lot of these efforts. Maybe, Garen, you could touch on what can be done to address potential higher costs with these types of systems?

    Garen Ewbank:
    When we talk about these carbon taxes, you'll see now accounting systems are looking at what we call the ESG, the environmental, sustainable, and governance of the corporations, and that's something new that's coming in and be implemented along with some of these carbon taxes that we're probably going to see. Haven't seen many of them yet, but our government always needs more revenue, and this has been an easy way for them to do it. I hate to say that, but there you go. Okay. So what are we going to do to address the higher cost of the ground source heat pumps?

    The ground source heat pumps are just units. Okay? Now they can be unitary. They can be giant chillers that are reversible. I mean, they take a lot of forms. They can use various types of refrigerants, and so we can come out with moderate temperatures with 410A, or we can come out with extreme high and low temperatures with CO2. So there's a lot of things that we can do there, but probably the easiest way to lower the first cost is to create what we call community loops, and all it is a big convective circulation circuit that has plug and play devices like a ground heat exchanger, maybe a sewage water heat recovery rejection system, something like that. And when we do that, along with the diversity of the buildings that are connected to this community loop, we find that we have a lot less demand on the ground heat exchanger because of the way we attach these devices.

    An example at one of the campuses that we've done, if we'd done each building and design the ground heat exchanger just for the buildings, we would've averaged about 217 feet of vertical borehole per ton of installed HVAC equipment. Using this community loop, which we call an ambient temperature loop, and it's a generation five, we're operating at 77 feet per installed ton. Now, that's a pretty big cost reduction right there. You don't have to know the numbers. You can just see the scale of that change, and so when we go through this, we've always got to consider the life cycle cost of these systems, which is the first cost, energy cost, and maintenance cost, and replacement cost.

    The closed loop ground heat exchanger does not wear out, and it can last maybe 100 years+. We don't know. Now, I put my first one in the mid-70s. Okay? It's still running, running well. And so how long is it going to last? We don't know, but that plastic pipe, high density polyethylene, is going to last very, very long time into the ground. So we got a kind of a problem here. How does Harvard figure out to value or salvage value the replacement cost of the ground heat exchanger? Because its value goes up with time, not down.

    Steve Hamstra:
    I think one of the areas that Garen and I have also done a lot of work in our careers are different ways to couple with the earth, and different types of heat exchanger configurations, whether they're vertical, or horizontal, or directionally bored, or they're hybrid solutions that say combine closed loop earth heat exchangers with other heat exchangers that access, say, groundwater. I was recently involved in a project. It's a good size Boys and Girls club renovation here in west Michigan. We designed a ground coupled heat pump system with both a conventional closed loop heat exchanger, where we drill vertical holes in a grid, and we're running four or 500 feet down with the high density polyethylene pipe that Garen mentioned. And the bids on that came in right around $800,000.

    We did an alternate bid where we were able to keep the closed loop configuration, but take advantage of copious amounts of groundwater on that site, and we took that heat exchanger from $800,000 down to $300,000. So there's opportunities depending on how many different tools you have in your box. And sometimes in our industry, when we have something that works, we just tend to do that over and over again, which there's nothing wrong with that. We're all liability averse, but there's also a place, especially now, for us to consider new and emerging technologies, and can we safely apply them for our clients, and how do we then measure the benefits over time?

    Pretty soon, we're going to talk a little bit more about multi-source heat pumps, and that concept of having systems that adapt to the environment. We'll hit that, and Garen mentioned district loops. We're going to come back to that as well. Garen, what about financing options?

    Garen Ewbank:
    Well, we have a lot of options out there. In the past, we've looked at third party ownership on bill financing, the various programs where you could attach it to your property taxes for commercial and residential, but we're seeing now groups come in offering sustainability as a service. And what that means is that if you have a system that you're proposing that's quite efficient, and changes your operating costs considerably, and lengthens the life of the equipment, they may want to do that, and we're seeing that happen quite a bit.

    Further, and this is breaking news, guys, in New York, the utilities, the gas, and electric, and I suppose the sewer and water, and everything else, can now own and operate these large ambient temperature loops and connect up facilities and communities. This is new. This is big, and this is something that's going to change our industry. So it moves that third party financing back to the utilities, which are really good at raising money. Okay? And simple systems like a ground heat exchanger, they can operate, so that's kind of what I'm thinking. Steve. What do you think?

    Steve Hamstra:
    I'm very excited. Yeah. That legislation was the ink is hardly dry on that. That just happened this week, and it is going to be a game changer in New York, and I think a model for communities nationwide and states nationwide that want to make it easier, take those market hurdles out. We are seeing as well a lot of utilities offering rebates for ground source projects, and this can be applied to both new construction generally and retrofit. So my fellow architects and engineers that might be listening, keep that in mind, think about those potential financial incentives that your client's utility may have available, and make sure somehow that's getting addressed, and if it's extra work for you, maybe it's extra fees as well, but that's a possibility. Tax incentives, tax credits, accelerated depreciation for commercial projects, you pretty much can write off the whole value of the HVAC system in five years.

    That can be huge in many applications, and in some projects, this pencils out to be a positive cash flow right from the beginning, as you factor in your reduction in costs versus paying off the loan, if you will. There's additional federal level tax incentives being proposed in the Senate, in the House, and so this, not unlike the bill that Garen mentioned in New York, this is a moving target. And I would encourage folks to try to stay tuned in to the industry to keep track of where this tax stuff is going, because it's pretty big. One of the proposals was trying to move ground source heat pump tax incentives on parity with solar photovoltaics, which is 20, 30%, and we've typically been down at the 10%, 20% roughly for ground source equipment. So some potentially very, very large, large changes. We touched on this idea of a multi-source heat pump. Garen, can you put that into terms we can understand?

    Garen Ewbank:
    Yeah. Steve, when we talk about these incentives, you want to remember that there are various incentives for residential and commercial, and they can be quite beneficial as we go through these things. Also, there are additional incentives from utilities and other people to help them manage their load on their grid, and that's going to become even more important, but when we talk about multi-source heat pumps, there's a lot of things out there, but we have had for quite a while what we call dual source configurations, where you could use an air source component for the heat pump or switch to a ground or water source component. Okay? They don't do both at the same time. They just do one or the other, but they can be quite efficient.

    I was on a research project that EPRI did with a southern company, and we looked at some ground source heat pumps compared with some VRF heat pumps, compared with some air source heat pumps, and I noticed that there was a time of day when the air source heat pumps got quite efficient, even better than the ground source heat pumps, a very limited time, and it got me thinking. If we had systems that were what I call polymodal, okay? Which means they can do air source heating, cooling, ground source heating and cooling, and move heat, transfer it from the ground to the outside air or the outside air to the ground, with that we can potentially reduce the earth couplings by 50% to 75%. Another company that Steve and I are involved in, we've actually had what we call a Frankenstein or the alpha unit running, and the ground heat exchanger never got below 53 degrees and never got above 85 degrees in Tulsa, Oklahoma.

    Now, that's pretty phenomenal. All right? So we could have greatly lowered the length of the ground heat exchanger. I still would've had to had the flow through it. So I might of had to have a little bit bigger pipe had I done that, but that is one way along with the diversity on community loops or ATLs, where we can greatly lower that first cost.

    Steve Hamstra:
    And as we think about ground source heat pump systems, many of us, because we've done say vertical closed loop for 95% of our projects, that's what we think of, but really if we can access a fluid flow, be it a closed loop ground heat exchanger, or Garen mentioned wastewater energy transfer, typical city wastewater is often in the 65 to 75 degree Fahrenheit range year round, and indeed the horizontal sewer mains are in essence buried heat exchangers themselves surrounded by earth that tends to moderate the fluid temperature in those pipes. So this can be a great way to also serve as a boiler, a source of heat, or a cooling tower, a place to get rid of heat, and there are some huge projects globally. Vancouver has got one that I think it's 8,000 tons, and millions of square feet of facilities that are basically heated and cooled using wastewater.

    But ambient temperature loops in a district configuration, if we have a nice mix of commercial and residential on that same loop, we can have folks that are in essence in the cooling mode while other folks on that same loop are in the heating mode, and that can really help us out. And this type of equipment, this dual source stuff, is starting to hit the marketplace. At AHR, the ASHRAE conference in Las Vegas this past February, we saw one main manufacturer that had a dual source, a commercial scale dual source, i.e., air source, and water on display in their booth.
    So it's coming and in essence it's available in some forms right now. Ambient temperature loops, thermal district solutions, Garen, maybe we established a little bit of a definition there on what we're talking about.

    Garen Ewbank:
    Yeah. Thank you, Steve. That's a good lead in, because this is where the industry probably is going to be going. What we try to manage these ambient temperature loops is to maintain the fluid temperature inside this big convective circuit. Okay? And it stands there by itself. It has its own pumping arrangement. It'll have maybe a 2N+1, a 3N+1, but an example will be on the 2N. The two pumps will be set at 60%.

    And so when we're flowing these things, we start taking advantage of the various affinity laws for pumping water. When, of course, if we're variable speed on the HVAC equipment inside, we again take advantage of that, and we start falling into what we call the 50/90 rule, which says that 90% of the time, the facilities are at 50% of the load or less, and we're finding that. And particularly if you look at your BIM data on temperature, you will see that, and the idea is to keep those heat pumps happy. If we need some help, we can bring in other plug and play components with a one pipe connection. All the facilities are connected to one pipe. All the plug and play devices are connected to one pipe, to this ambient temperature loop.

    So you have three components. You have the buildings. You have the ambient temperature loop, and then you have the plug and play devices, which would include a ground heat exchanger. They simply come on as they're commanded to keep the heat pumps happy. In other words, the temperature inside that convective circulation circuit at about 50 to 90 degrees. Next, while we're connecting all these buildings, if you'll look at some of the current National Renewable Energy Labs and Rocky Mountain Institute Studies, we're going to find that diversity has a big play in reducing the sum of the loads.

    In other words, as we add up all the building's loads, it does not equal the peak block load of the sum of the buildings. It's lower than that. They published a really good publication on that. You're welcome to go get it, search it out at NREL, but it's really good. But even further than that, we have to look at changing from a sink and source solely on a ground heating exchanger to the ambient temperature loop using energy storage, a thermal battery, whatever you want to call it. And this thermal battery can have the wastewater on it. It has the phase change materials on it. It can have solar PVT, and the T portion is what would be important.

    There's a number of other things, but to understand how that battery will charge and discharge, Rick Clemenzi and I developed what we call the advanced thermal conductivity testing method, and really what its goal was was to determine the volumetric heat capacity of that local heat exchanger. So with that, now we can tell, and we can directly measure how these thermal batteries are going to charge and discharge. In other words, how they're going to give heat, and at what rate, and how they're going to accept heat, and at what rate, and that's something new for the industry. So we'll have some white papers coming out here very shortly on one of the campuses that we've been an extremely efficient system operating on, if that makes sense.

    Steve Hamstra:
    And as Garen noted there, as we start looking at all this various thermal resources that may present themselves, we want to make sure that we're looking at everything. So we've touched on wastewater energy transfer, but there's also surface water energy transfer. Is there flowing water? Is it on a river, a canal? Is there a lake that's sufficiently deep that we could use it as a heat source or a sink? Certainly groundwater. In some areas, groundwater is easy to access and has good chemical properties that aren't going to cause problems, and if we can just alter its temperature slightly, and then return it to the aquifer, it's a good way to go.

    Solar PVT, Garen mentioned that. So that's the combination of solar photovoltaics plus an additional hydronic panel, if you will, behind the PV panel. And as we think about that, if we move fluid behind that panel when the sun is shining, we're going to get two benefits. We're going to get some beneficial heat that we could potentially use in our district energy system, but we're also going to cool the solar PV panel itself. And we know that as PV panels get warmer, their efficiency goes down. So by keeping their temperature in a better range, if you will, it's been demonstrated that we can increase the annual output by 3% to 5%, but this can be used not only as a heat source, but when the conditions are right as a way to get rid of heat.

    So think about what happens when the sun goes down, and the air temperature drops, and we also have radiant heat loss to the cosmos, truly up through the sky. We can dump a lot of heat without turning on fans, without evaporating water, or adding chemicals to water, or being concerned about legionellae growing in a cooling tower. And so there's significant benefits, both on the heating and cooling side, and we have several projects that we're working on, but this has been done.

    Again, this is technology that's been available for a number of years and has been applied repeatedly, so I would encourage practitioners, do some research, and do the searches on solar photovoltaics plus thermal, and there's a lot that's been happening in Europe as well as here in the US. Garen, did we cover thermal storage enough, or is there anything else you want to hit on that?

    Garen Ewbank:
    Well, Steve, I do have a couple of items I would like to mention when we get into this. Now, you talked about the black sky radiation. Okay? That's a really efficient way to dissipate or send heat out. The problem is if we remove that heat from our system, it's no longer available to be recovered. And so we got to figure out how much do we need to recover, and what do we need to vent?

    And so knowing those loads on these systems, and Steve is getting pretty good at a little piece of software out there that he can design and look at these various loads of various facilities that are connected to it, but the idea is to understand how to quantify and design to that thermal energy storage. For example, a heat pump that's really efficient may have a coefficient of performance, CoP, of maybe five, and we're not going to improve that with current refrigerants and current construction that we have in the very near term, but if we look at the integrated coefficient performance in kW as a standard and get away from SEER, HSPF—all these different things that we talk about to the consumer and just confuse the heck out of them. All right? Maybe if we had a standard called integrated coefficient performance in kW, we'd have a common language.

    Now, with this thermal storage, we can increase the system's thermal efficiency considerably. We do not have to generate heat. We don't have to burn something to get heat. We don't have to evaporate lots and lots of water to reject heat, run giant fans outside. There are just ways to do this that are much more efficient than what we've been doing in the past, and that's kind of what I would like to say about that.

    ASHRAE Journal:
    Thanks for listening to the ASHRAE Journal Podcast. We want your ideas. What topics do you want to hear about, and who do you want to hear them from? Email us, your ideas at That's

    Garen Ewbank:
    Steve, that moves on into the community scale projects. There's a lot of these going on now, particularly in the Northeast of the US. We see gas companies in the Northwest of the US also trying to figure out this little conundrum. You know what they're finding? They can make money off these systems, and they can make them of an asset that lasts longer than their gas lines. Now, that's pretty interesting. Okay? The whole idea is to keep your meter on the customer. Okay?

    Much like some of the policies we did in the mid-90s, the federal buildings, and so let’s go through this, but these community skill projects are starting to couple up, low density, medium density, high density, mixed use, and when we do that, as we go into the higher density and the mixed use, we're finding that the loading in the Northeast is about balance between heating and cooling, which means that big ambient temperature loop or that convective circulation loop just stays there and flows fluid happily. And so we've got a lot of different groups looking at writing standards and codes for these district solutions.

    And if we go through this, and people listen to the participants in the industry as they write these codes, we're going to get some really beneficial things coming out. IAPMO is one of those. They've got a couple of them going. We have a whole section that's going to be included later on ambient temperature loops. Now, ASHRAE looking at this also, and we encourage them to get further into that and understand it fully, but that in truth, probably Oak Ridge National Labs, Pacific National Labs, National Renewable Energy Labs and some others are really doing a good job through the DOE to bring this all together for the industry.

    So you're going to have codes, then down to standards, and then down to ASTMs, and down to the specific components of. It's all going to be addressed, and we'll be able to do that. I hope that helped, what I was talking about, Steve, on these things.

    Steve Hamstra:
    It did.

    Garen Ewbank:
    And you got some new technologies maybe we should talk about.

    Steve Hamstra:
    Yes, sir. Well, and a lot of people ask. They say, "Hey, my building is an older building, and it was designed with a hydronic heating system that's looking for water 180 to 200 degrees Fahrenheit. How do I retrofit that and do that with a heat pump? The short answer is there is technology to do it. The longer answer is, well, depending on the solution, the system efficiency will be impacted. So Garen will touch on some refrigeration changes in the marketplace that are coming up, but our current refrigeration picks, say 410A in 134A, were pretty much limited to say 140 to 150 degrees Fahrenheit, and beyond that, things start getting a little squirrely.

    And refrigerants like CO2 and even ammonia, those can be used for relatively high lift applications, and again, as we look across the big pond to our colleagues in Europe and elsewhere, they have industrial scale heat pumps that are easily doing 200 F and warmer, then using that in an indirect boiler application to make low pressure steam. That technology isn't readily available here in the states yet, but it's been in use for a couple of years or more elsewhere. So as market pressure drives it, I'm hopeful that we're going to see that as well. But there's also as Garen and I as regular practitioners are looking at retrofits all the time, we're always looking at, well, can we modify that existing building's terminal devices to make them function at lower hot water temperatures? And usually heating is the challenge more than the cooling side.

    And we've employed several different methodologies for this. You may have a hot water coil and a chilled water coil. Usually the chilled water coil has more rows and fins and is a bigger coil, have more capacity. A, can we leverage that chilled water coil during the heating season? Can that be tied into both a chilled water system, as well as a hot water system with some changeover occurring, but can we leverage that cooling coil to provide heating at a lower entering water temperature? We've also done twinning, where we'd add a secondary hot water coil in front of or behind the existing hot water coil, and then we take all the water that flows through the original coil, and we pass that through a second coil.

    So in essence, we're adding more rows of heat transfer. That's another way to start pulling those temperatures down. And certainly anytime we're looking at major HVAC retrofits like we're talking about today, look at the building as a whole. I say that the first three steps of making a high performance building is number one, reduce the load. Number two, reduce the load. Number three, reduce the load. Number four, look at waste energy recovery. Is there something throwing away that we could use in another form, in another way?

    And then after you've kind of worked through those first four steps, then we start looking at, all right, what is the HVAC solution that fits best? And if there's a renewable energy component, that's when it makes the most sense to apply it. After you've reduced your loads sufficiently, you may find that the same size solar array instead of providing 20% of your annual energy could provide 50% or more, because you've reduced the loads and then applied energy recovery and high efficiency equipment. So often, again, as ASHRAE practitioners, we talk about refrigerants a lot, but things like CO2 as a natural refrigerant, been around forever.

    I was told a story the other day that I hadn't heard before, and it involved Japan, and Japan made a very concerted effort due to the high amount of their residential housing stock is all wood frame construction. They wanted to move to non-open flame or burning heating devices for domestic hot water, and what they did is in essence made it illegal to burn gas to heat domestic hot water, and it sparked the generation of CO2 driven heat pumps, or CO2 refrigeration in heat pumps. And we see a couple of major manufacturers that we would recognize their names here on electronics and a lot of other things, that have been making these for decades in Japan.

    And we're just starting to see the birth, I think, of a new group in the industry here in the US that is looking at CO2 as a viable refrigerant that has many advantages with regards to efficiency, and global warming, and not being toxic, and not being flammable, and allowing us to hit very high temperatures or very low temperatures depending on the application. So maybe, Garen, touch on what you're seeing happening in the world of refrigerants that we use in these heat pumps.

    Garen Ewbank:
    Steve, thank you. There's a lot of change coming on, and our manufacturers, they have to adopt these changes, and it takes a while, guys. There's a lot of certification and everything that's going on out there. Mainly what we're using, which we all know, is 410A, but as we move into the 32 or 454B, on forced air systems, they tend to work really well, because if you need more load, you can run it a little bit longer, get a little bigger unit, whatever, but if we need those higher temperatures on those hydronic loops, we're going to have to consider what makes the most sense. And we're not there yet as an industry. I'm really liking the CO2 stuff for that portion, but we still got to back up and think about those forced air systems as we go through this.

    So as we go into this, we need to start talking about communities with high performing buildings, energy loops, and we got to design a pathway to the lowest energy use intensities, EUIs, and the lowest energy intensity of economies. And so we got to start some master planning. Okay? There's about 10 things that we have to go through in this master planning to make these community loops, ambient temperature loops, district loops, whatever you want to call them. They would be called an ATL. And we've got to figure out what is a high performance district.

    It's one that starts lowering the integrated CoP and kW in a major way, which is for the building itself would be the EUI for that facility, and we average them all out and see what we're looking at across the whole system. That's one of the things we can talk about, but there's some real value to this proposition, because we're talking about equipment that starts lasting a lot longer, performing more efficiently, and delivering better comfort to the space. These high performance buildings that we're getting into, guys, on the grid interactive enabled buildings, or the GIEB buildings, we can now start managing the demand, not only on the building, but on the combination of all of the buildings.

    That becomes a benefit for these high performance districts. That leads us into beneficial electrification that is coming down to scale. Now, how fast it's going to get here, and what it's going to do, we don't know that yet, but it's seeming to go at a pretty rapid pace right now. Now, to achieve that scale, we got to put some pipe in the ground, guys. Okay? And we got to connect heat, pumps up to it. They can be cooling only heat pumps like a big old chiller, something like that.

    The boiler becomes a little bit more of an issue, but we address that also. So as we get into these, these challenges for these districts aren't as insurmountable as most people would think. And I think with utilities coming into this game, you're going to see some pretty rapid change. Next, we need to start talking about fostering support and assembling the team. So we've got to engage a team. Where we going to do this? What are we going to do, and why we want to do that?

    And I'm going to suggest something new to our industry. I think we need to start and create sustainable development operational teams. And this is just like the IT and the other industries have done when they moved away from just putting their software in, running it, and keeping their updates in. The development operations starts bringing in the new systems along and parallel with the old systems, and the old systems go away. And so that's what we're probably going to be doing as we get these ambient temperature loops in and all these plug and play devices, and you develop a plan and a procedure and look at these things. There's a lot of stuff that's out there, and if we get into these things and understand that we really want to drive these operating efficiencies up, it's easy to do.

    You just have to set your goals and get your principles in place, because you have some operational goals, and then you'll have some aspirational goals. And if carbon tax comes on, that aspirational goal is going to move into a practical goal real quick. Okay? And so we have to look at that. So you want to get your first project right, and to do that, you select the best technologies to give you the most bang for your dollar, really is what we're heading at. Then we can develop some financial and business models, and there's a lot of robust models out there. Harvard is still having a hard time figuring out that ground heat exchanges value on salvage, but anyway, the energy development models we're looking at are getting really attractive, because if we green up our grid, we have a lot of reduction coming on on carbon, which is a good deal.

    And so these financing approaches lets us do that probably in a fairly quickly to employ manner. Next, we move on to the utility engagement. Ah-ha, hadn't had that before, had we? Now we do. In the past, they would give you a little bit of a rebate for this, or that, or whatever, but once we understand that these relevant utilities have goals out there that they have to meet, and that our society has goals that they would like to meet, we can pretty well correlate these things under that sustainable development operations team to get into this. Sustainable development operations have been called a lot of things in the past, the master value engineering, complex systems engineering, and everything else, but what it really is how do I marry up the operational aspirational goals for this facility as we move forward with these devices that are going to go in there?

    So the utilities can do this, and it really works well, because they can plan these things out. Once we do that, we can get our rates and our metering options pretty simple. All right? Your power cost adjustment factor might start going away as we one, green the grid, and two, recover wasted energy, and reuse it, and reuse it, and reuse it. Okay? So we're going to identify those programs, and then we've got to engage the utility people to understand how this all works. It works pretty well, but there hadn't been a lot of planning on that, and we're going to get into that.

    So we have a number of new technologies, programs, and business models that are out there that are going to happen. With that, then you're going to develop your energy master plan, and there's three points there, and the energy master planning process has to be about those operational and sustainable goals. Next, those implementation and success factors. Guys, if you're not measuring it, you can't do anything about it. And so we got to look at that as we go through these things, then we have to look at our operations planning. Are we taking care of the needs for the comfort, for the humankind that's in that environment? Yeah, we want to do that.

    After we've gone through that, we're going to start planning for our energy demand and efficiencies, and when we analyze this and make our approaches, we're going to let the best technologies win. That's the whole point to this thing, and the energy use intensity is really important, because on another campus that we've gone in on an existing system, we took the condensing return water line and made it into an ambient temperature loop, and on one of the buildings, we lowered the EUI from 85 to 23. Now, I think that's valuable in our society, guys. And so we can go through that, and consider these various things, and what they cost to run and install, and everything else, and how they integrate. And usually we integrate these systems on these district loops, community loops, ambient temperature loops through one pipe connection, so that we can move that energy as we want to go around it.

    It becomes kind of straightforward, but once we move into the district or the ATL where all the facilities are, we got to look at those buildings, and there's various iterations that, of course, we need to go through, that may make a lot of sense immediately. And sometimes it's kind of okay to go in and look at your structure. Do we need to make changes? Of course, everybody says, "Do the lighting. Do the windows." Well, that's low hanging fruit, and that's the beginning, but there are a lot of other ways you can do that. Once we move into the devices that do the heating, and cooling, and outside air management, and domestic hot water, we can really couple up to these loops and do a lot of good for everybody.

    So those considerations and integrations are out there. We just have to do our math and go through them. All right? If we're trying to get a bunch of renewable energy at the site, you're going to be limited, but if we do that as a plug and play component to a large community system, hey, we can spread these things out. Your thermal solar PVT thermal might be three or four miles away, but it's managing the temperature in that loop along with providing power to pump that loop and move that energy, or put it back into the grid, if there's some advantages to selling it back to the utility for the power. You can do that. So again, we go through those considerations and integrations, then we end up planning for the grid integration.

    And so we're going to get the grid interactive and the thermal interactive enabled buildings to couple up, and we are doing this in, well, one of our other companies that Steve are involved in, and we're throwing a lot of stuff out here, but it's simply global energy management, and what it does is it marries up all these technologies, and at the time of use, picks the best technology that has the lowest energy index, and that is pretty straightforward and easy to do. So we can do those things, but this last thing for the electric vehicles, that's a real stumbling block, and if we don't have a real good way to store it for those EVs, we may have a problem in there.

    So there are a lot of case studies that we can go through, and we can talk about, but to begin with, if we look at a new facility, we want to first define the operational and aspirational goals. Next, we want to quantify the energy at risk. This is missed many times. All right? And this energy at risk can be something that can be handled maybe pretty simply, or it could be very costly, depending on how valuable it is to be online. Now, if you have a server farm, you better be looking at energy at risk. If you have a hospital, you have a nursing home. So if you have some other lower level things where you can let the temperatures rise or go, maybe a tire changing shop, where you're going to make the guys work in the heat or the cold, I guess you could do that, but from that, once we've identified that risk, we're going to create these sustainable develop operation teams with goals, authority, responsibility, and funding to implement these changes, then we're going to do our basic design that we're going to create. You know.
    All of us have done those time after time, after time, and I want you to quit pulling them off the shelf, and thinking about this, and get into our iterations. So with that, we're going to run the basic energy modeling, and then we're going to engage that sustainable development operations team, or SDevOps, to achieve those goals. How are we going to get there? Then we're going to begin the iterations for the structural facility loads reductions, and that can be numerous. Okay? Then we're going to get into our iterations on the operational load reductions. Do we have to do this all the time? Do we need to do it here? There's just a lot of ways we do that, and with that, we also add in our iterations for our heat sink and source technologies or the plug and play components.

    And so we're going to measure those results with the implementation of the individual technology, and we're going to publish those results back to the owner or to whoever is really considering it. We'll either accept or reject that work. Now, if we go into an existing facility, it becomes a little bit different, and this is how we think this process through. Firstly, we define the operational and aspirational goals. We quantify the energy at risk, and we're working for a large oil and gas company that's doing a campus right now, and their gas measurement group has to be online all the time. So their energy at risk is quite high on that one facility. Okay, over in Suzie's office, in the other building, not so high. Okay?

    So we go through and define these things that can be done process by process. And again, we're going to create that SDevOps group, give them the goals, authority, and responsibility for funding. Now we get into the meat of the things on these existing facilities, and, guys, when you get out there, if you're going to change something, you need to measure it, see if you know what you got. And so probably the first thing would be a recommissioning exercise, and confirm all the devices and their operations. Are we getting accurate reporting? Then we move into continuous measurements as we go through this, to see that those existing operations are running properly, so that continuous commissioning can keep on going. And we want it to keep on going, which leads into the fault detection and diagnosis to solve existing issues.

    These pop up all the time, things that it's hard to think about, but the FDD becomes very important, but it's got to report back to this development operations team to solve those issues in a proactive, in a beneficial way, and the goal, again, is to lower the EUI. We'll begin to do some iterations for the structural and facility loads, and then the operational load facilities, and then the heat sink and source loads with plug of play devices. And again, we're going to implement these in orders of the best technologies, and they will win. Does that makes sense? We're going to measure the results with the implementation of each technology, and we're going to publish it, then we're going to accept or rework the implementation, because if we didn't get our goals, we got to do something else. So that's kind of where that all leads to, Steve.

    Steve Hamstra:
    It was great, Garen, because I think you've created an outline that people can listen to and that it makes logical sense how you built that up. And I think as we wrap up our conversation here today, I want to share a little bit about the ASHRAE Technical Committee 6.8 and some of our recent activities. So we've just finished rewriting our chapter in the Handbook. So you'll see that in the 2023 Handbook, I believe, and one of the things that we've been working on is a clarification in the industry that ground source heat pumps are different than geothermal power. And we cover both of those in our chapter, but in essence, we focused today on pretty much on ground source heat pump technology.

    The geothermal power technology, or we sometimes call it hot rocks, is where we're going much deeper in the earth, and we're taking advantage of high temperatures to potentially create steam or drive other forms of engines that can generate electricity. If you think of Finland and some of these northern Scandinavian countries where they also have steam like that, they're providing district heat, energy, et cetera. So that's the geothermal side, and you'll see some clarification in the new Handbook chapter that hopefully makes it easier for people in the industry not to mix up those two technologies. We tend to use geothermal and ground source kind of interchangeably, and we have done that for decades. So it's probably going to take decades for us to undo that.

    We're working on several potential research projects that have to do with flushing, flushing large lines, what flush velocities are needed, and ASHRAE has slowed down research a little bit because of the pandemic and just availability of funding, but that's starting to ramp up. So stay tuned, I think there's some exciting stuff that will be passing through. ASHRAE in this technical committee. Same time, I would say we're looking for people to get involved, and we've had several of us are maybe a little more gray around the edges, and I'm excited that our new chairman, Howard Newton, is my age, but that's okay, Howard. You're great, but then we've got some younger guys, Roshan Revankar and Brendan Hall. Roshan being the vice chair, and Brendan is our new secretary, and I'm excited to get some younger folks more engaged with the activities of the TC, developing new standards, looking at new technologies, and making presentations.

    So if you have an interest in this area at all, please reach out to us or ASHRAE, and we can outline how you can get engaged, and the engagement may be you're just sitting in and listening to meetings, or you're a corresponding member, or you're a voting member, or you get into a track to serve as an officer, so all are great, great opportunities. So Garen and I really appreciate this opportunity to share some thoughts with you today on our industry, and the future is bright. We see what in the past was kind of a slow or a minimal market penetration of ground source technology is once again starting to accelerate, and we're seeing new technologies that are going to make that even better and easier, I believe.

    The question is as practitioners, are we going to equip ourselves with the tools we need to support society as we seek to achieve these goals? And that's a challenge. Some of us are maybe the latter parts of our careers, maybe are not going to embrace technology as quick as we're hoping some of you youngsters would, so please, get engaged, join ASHRAE, and we look forward to meeting you all.

    Garen Ewbank:
    Yeah. And, Steve, to follow up a little bit, I'd like to send greetings to every member out there, particularly from Oklahoma State University, the dean of the college of engineering, architecture, and technology. I serve on a board with him, and we look at things on down the road and make some plans, and what are going. In fact, this week, I'm missing a meeting in Houston, but there you go. Maybe he'll forgive me. Further, the Northeast Oklahoma chapter for the American Society of Heating, Refrigeration, and Air Conditioning Engineers would extend our greetings to the whole body. And if you're in Tulsa, look us up, come to our meetings. We have some great lunches and some great speakers, and so we're pretty active. We do a lot of stuff all the way down to involving the youth, and the scholarships, and things like that, so great organization. Sometimes engineers have to have a little break and do some enjoyable activities, and trust me, Tulsa does that.

    Steve Hamstra:
    Well, and thank you for that, Garen, and I'd like to emphasize for those that don't know, Oklahoma State University really was where the international ground source heat pump movement was birthed, and a lot of the, no pun intended, groundbreaking research and application was done at OSU, and standards were developed there. It was the home of the International Ground Source Heat Pump Association for many years. That's been spun off now into a separate entity, but in the industry, we all owe a big thank you to OSU, and we stand on the shoulders of some great pioneers like Dr. Bose and others, so thank you for bringing them up here.

    ASHRAE Journal:
    The ASHRAE Journal Podcast team is editor, John Falcioni; producer and associate editor, Chadd Jones; assistant editor, Kaitlyn Baich; and associate editors, Tani Palefski and Rebecca Matyasovski. Copyright, ASHRAE. The views expressed in this podcast are those of individuals only and not of ASHRAE, its sponsors or advertisers. Please, refer to for the full disclaimer.