ASHRAE Insights

The final reports for these projects are available for free for ASHRAE members. Members can log onto ASHRAE.org and go to the Research link under the Technology tab. The ASHRAE Transactions papers are available for $5 for ASHRAE members at www.ashrae.org/bookstore.

1207-RP, An Experimental Investigation of Pressure Drop and Heat Transfer in an In-Tube Condensation System of Ammonia with and Without Miscible Oil in Smooth and Enhanced Tubes

With global bans and restrictions on CFC and HCFC refrigerants, ammonia is becoming a strong candidate for use as a refrigerant. To assist engineers in designing new technology refrigeration and air-conditioning equipment for various markets that are open to the application of ammonia (i.e. refrigeration condensers, HVAC condensing coils, and packaged chillers, supermarket refrigeration systems, etc.), an ASHRAE research project develops heat transfer and fluid flow data that is currently not available.

A technical paper was submitted for future publication in HVAC&R Research.

1207-RP was sponsored by TC 1.3, Heat Transfer and Fluid Flow. The principal investigator was Predrag Hrnjak Ackerman of the University of Illinois.

1218-RP, Numerical Methods for Low Frequency HVAC

A project that set out to improve the accuracy of calculating effects of individual HVAC components on the noise and vibration characteristics of duct systems has been completed. Most of the current guidelines in the ASHRAE Handbook are the result of application experience and are semi-empirical. This project concludes that numerical modeling of the acoustical characteristics (i.e. transmission and insertion losses) of HVAC components is now practical with state-of-the-art noise prediction software, and results are considerably better than the current formulas and data tables. These numerical models can dramatically reduce the need to build and measure HVAC components and systems to establish their acoustical performance.

Two technical papers (Vol. 113(1), DA-07-002 & DA-07-003) on this project were presented at the 2007 Winter Meeting and are now available.

1218-RP was sponsored by TC 2.6, Sound and Vibration Control. The principal investigator was Dr. Andrew Seybert of the University of Kentucky.

1309-RP, Development of Solar Radiation Models for Tropical Locations

A recently completed research project presents a model suitable for predicting hourly solar radiation (global, direct, and diffuse) for tropical climates. Past studies comparing existing models to measured data either have not compared accurately or simply do not exist for many low latitude locations. The development of these models for tropical locations will provide more weather data for use in building energy simulations and eventually improve building design in these locations.

A technical paper (Vol. 113(1), DA-07-057) on this project was presented at the 2007 Winter Meeting and is now available.

1309-RP was sponsored by TC 4.2 Weather Information. The principal investigator was Moncef Krarti of MK Associates.

1252-RP, Interaction Between Dynamic Electric Rates and Thermal Energy Storage Control

A recently completed ASHRAE research project developed and evaluated a control strategy for thermal energy storage (TES) systems that works with real time pricing (RTP) utility rate structures to maximize operation cost savings. The control strategy requires relatively low-cost measurements and little plant-specific information, is computationally simple, and ensures that building load requirements are always met. The project illustrated typical operating cost savings of 25-30% compared to more common strategies typically employed for TES systems with RTP structures.

Technical papers on this project were published in HVAC&R Research (Vol. 13(4), Jul. 2007) & ASHRAE Transactions (Vol. 113(2), LB-07-037) and are now available.

1252-RP was sponsored by TC 7.4, Building Operation Dynamics. The principal investigator was Todd M. Rossi of Field Diagnostic Services.

1200-RP, Optimized Operation of Chiller Equipment in Hybrid Machinery Rooms and Associated Operating and Control Strategies

Natural gas absorption or engine driven chillers can be used in hybrid chiller plants to reduce the peak-demand and peak-energy usage associated with electricity powered chillers. However, there is little guidance for supervisory control and optimization of hybrid chiller plants. A recently completed ASHRAE research project developed a set of operation strategies that minimize operating costs in hybrid chiller plants for a wide range of conditions. The project showed that using optimized control of hybrid cooling plants can reduce associated annual operating costs by up to 50% in some instances. These control strategies can supplement information for all-electric equipment chiller plants in the Chapter A41 of the ASHRAE Handbook.

Technical papers were published in HVAC&R Research (Vol. 13(4), Jul. 2007) and ASHRAE Transactions (Vol. 113(2), LB-07-011) and are now available.

1200-RP was sponsored by TC 8.3, Absorption and Heat-Operated Machines. The principal investigator was Mr. James Braun of Braun Consulting.

1076-RP, Diagnostic Test and Analytical Methods for Resolving Fan/Motor Vibration Problems in Air-Conditioning Units

An ASHRAE research project is now complete which set out to better understand and predict fan vibration problems that can occur as a result of the interaction between the fan impeller and the fan motor / fan structural support system. The project compared experimental modal analysis and finite element analysis (FEA) of a fan blade and fan-motor unit. The final report provides a list of recommendations to help assure good correlation between FEA and experimental analysis.

A technical paper was submitted for presentation at a future ASHRAE meeting.

1076-RP was sponsored by TC 5.1, Fans. The principal investigator was Douglas Reynolds of the University of Nevada – Las Vegas.

1092-RP, Development of Procedures to Determine In-Situ Performance of HVAC Air Side Systems

Building energy simulation is increasingly being used to evaluate the effectiveness of energy conservation retrofits. Calibration of the simulation program to measured data is an important factor in substantiating how well the model represents data from a real building. A recently completed ASHRAE research project has developed a step-by-step, simplified calibration model to calculate long term energy consumption based on short term field energy measurement data. The procedure improves accuracy significantly, is less labor intensive, more cost effective, and more efficient than typical calibration procedures. The final report describes and validates the procedure in five case studies with existing energy simulation programs in various climates and various system types.

A technical paper was submitted for presentation at a future ASHRAE meeting.

1092-RP was sponsored by TC 7.6, Systems Energy Utilization. The principal investigator was Dr. M. Liu of the University of Nebraska - Lincoln.

1254-RP, Evaluating the Ability of Unitary Equipment to Maintain Adequate Space Humidity Levels, Phase II

Unitary products now offer designers many different enhancement options to improve dehumidification performance. However, designers have little guidance in making selections of these options to improve dehumidification performance for a given application. A recently completed ASHRAE research project evaluates the ability of 18 different unitary equipment options to maintain space humidity limits. Whole building energy simulations were used to analyze these options in seven commercial building types, with varying ventilation rates, in 10 climates. The study compares the relative performance of each system type’s ability to control humidity, annual energy use, and life cycle cost. A list of guidelines to help HVAC engineers and practitioners determine which equipment option is most appropriate is presented in the final report.

A technical paper was submitted for presentation at a future ASHRAE meeting.

1254-RP was sponsored by TC 8.11, Unitary and Room Air Conditioners and Heat Pumps. The principal investigator was Dr. Michael Witte of Gard Analytics.