ASHRAE Insights

Seminars at the 2007 ASHRAE Annual Meeting in Long Beach will cover applications and problems that HVAC&R professionals are cureently encountering. Among the leading-edge topics discussed will be the ground-source heating and natural ventilation. Both subjects fit within the Technical Program’s theme: “Conserving Natural Resource Use in Buildings.”

Ground Source Heat Pump Innovation

Imagine a total energy cost of 41 cents to $1 a day for your house.Thanks to use of geothermal heat pumps, energy costs for two test houses in Lenoir City, Tenn., are that low.

Information on five DOE Building America near-zero energy test houses designed, built and monitored by Oak Ridge National Laboratory (ORNL) is shared in a seminar.

“The lower heating and cooling loads in high performance houses result in lower ground loop requirements for ground source heat pumps,” presenter Jeff Christian, ORNL, said. “Placing loops in the construction overcut for the basement or foundation eliminates the cost of drilling or trenching normally associated with ground loop installation. This can dramatically improve the economics of this technology. HVAC contractors should explore the opportunities to work with residential developers in the planning stages. This could open up a whole new target client in addition to contractors and home owners.”

The seminar, Ground Source Heat Pumps (GSHP) for Sustainability, takes place from 11 a.m.–12:30 p.m. Sunday, June 24.

The high efficiency of GSHPs means that for a given space conditioning load, less energy is used, resulting in fewer pollutant emissions and lower operating costs than most methods of heating and cooling, according to John Shonder, chair of the seminar.

“When combined with other technologies, GSHPs can be instrumental in achieving net zero energy use in homes and buildings,” he said.

The seminar presents results of innovative projects using GSHPs along with the renewable resources provided by earth. It is sponsored by ASHRAE’s technical committee on geothermal energy utilization.

Timothy McDowell, Thermal Energy System Specialists, Madison, Wis., discusses use of ground storage of solar energy in a seasonal energy storage system in Okotoks, AB, Canada. The 52-house subdivision has space and water heating supplied by an innovative system that includes solar energy captured year round by an 800-panel garage mounted array, borehole thermal energy storage (BTES) as an in-ground heat sink for seasonal energy storage, and short-term thermal storage tanks as a central hub for heat movement between collectors, district loop houses and BTES.

Scott Hackel, University of Wisconsin-Madison, discusses optimization of hybrid geothermal heat pump systems, which build on GSHP technology by coupling conventional geothermal equipment with supplemental heat rejection or extraction systems. Such systems can achieve higher yearly average performance, resulting in lower energy consumption.

Natural and Mechanical Ventilation in Schools

When it comes to ensuring safe, comfortable environments for students, which earns a higher grade—natural or mechanical ventilation?

The pros and cons of natural ventilation are examined in a seminar, Natural Ventilation in Schools: Boon or Bust?, from 8–9:30 a.m. Sunday, June 24.

“Natural ventilation in schools is used to lower cooling and ventilation costs,” said seminar chair Chris Muller, Purafil, Doraville, Ga. “However, uncontrolled ventilation can allow contaminants to bypass filters and permit the introduction of excess moisture. Given the number of schools located in non-attainment areas for one or more of the U.S. Environmental Protection Agency’s priority pollutants, natural ventilation can present increased health risks to a large segment of the student population.”

The seminar looks at ventilation in schools from the standpoint of outdoor air quality, covers air cleaning requirements of ASHRAE Standard 62.1 and presents a case study.

“Although you may expect to pay more for the operation of mechanical HVAC systems vs. natural ventilation, ASHRAE Standard 62.1 provides design options that reduce operating costs while still providing for acceptable indoor air quality,” said Brad Stanley, Purafil, Doraville, Ga. His presentation is titled “Mechanical vs. Natural Ventilation in Schools: Less Can Be More.”

Jerry Lamping with the North East Independent School District in San Antonio, shares how the district uses only natural and mechanical ventilation with no air conditioning in gyms and locker rooms. Voters will soon decide whether to convert these areas to full mechanical air-conditioned spaces.

Michael G. Apte, Ph.D., Lawrence Berkeley National Laboratory, Berkeley, Calif., talks about Ventilation Considerations in Areas with Elevated Ozone Levels.

“As we get more information on reactions by oxidants to organic compounds and their by-products, the rationale to control ozone entry into buildings and to select materials less prone to ozone reactions becomes stronger,” he said.