Improving the Energy Performance of HVAC Systems in Operating Theatres by Using Heat Recovery Devices

Heating, ventilation and air conditioning (HVAC) systems in operating theaters use fully fresh air, and return air is not allowed to be mixed with the fresh air. Therefore, HVAC systems in operating theaters are inherently energy-inefficient. In this research, the impact of heat pipe heat exchanger (HPHX) as a heat recovery device on the performance of an existing HVAC system of an operating theater was examined. The existing HVAC system, Plant A, was redesigned by the added HPHX as Plant B and C and the most suitable design in terms of energy consumption level and provided air conditions was recommended for the system. A transient system simulation software (TRNSYS) was used for the simulation of the systems for a yearly operation of 8760 hours. Based on the results, the application of HPHX, Plant C configuration, could decrease the energy demand of the system and it is recommended to be implemented in the existing HVAC system. Moreover, it was shown that the HPHX integrated system improves the room and supply duct air conditions.

Keywords:

Energy consumption level; heating ventilation and air conditioning (HVAC) systems; heat pipe heat exchanger (HPHX); operating theaters; TRNSYS.,

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M. O. Abdeen, “Energy, environment and sustainable development”, Renewable and Sustainable Energy Reviews, vol. 12, pp. 2265–2300, 2008.
Y. H. Yau, “The use of a double heat pipe heat exchanger system for reducing energy consumption of treating ventilation air in an operating theatre-A full year energy consumption model simulation”, Energy and Buildings, vol. 40, pp. 917-925, 2008.
ASHRAE, ASHRAEA Standard 170P, “Ventilation of Health Care Facilities, American Society for Heating, Refrigerating and Air-Conditioning Engineers Inc.”, Atlanta, GA, 2006.
ASHRAE, ASHRAE Standard 62-1989, Washington DC, USA, 1989.
D. Bearg, “Indoor air quality and humidity control, Air conditioning, Heating and Refrigeration News”, 1992.
D. B. Shirey III, “Demonstration of efficient humidity control techniques at an art museum”, ASHRAE Transaction, vol.99, No. 1, pp. 694–703, 1993.
H. Abtahi, M. Jayanth, and M. K. Khattar, “Theoretical analysis of the performance characteristics of dehumidification heat pipe heat exchangers in air- conditioning systems”, American Society of Mechanical Engineers, Heat Transfer Division, (publication) HTD, ASME Proceedings of the 1988 National Heat Transfer Conference, Jul 24-27, Houston, TX, USA, pp. 311-316, 1998.
G. D. Mathur, “Predicting yearly energy savings using BIN weather data with heat pipe heat exchangers”, Proceeding of the Intersociety Energy Conversion Engineering Conference, Honolulu, USA, vol. 2, pp. 391-1396, 1997.
G. D. Mathur, “Enhancing performance of an air conditioning system with a two-phase heat recovery loop retrofit” Proceeding of the 31st Intersociety Energy Conversion Engineering Conference, Washington, DC, USA, vol. 3, pp. 2027-2032, 1996.
Y. H. Yau, “Analysis of enthalpy change with/without a heat pipe heat exchanger in a tropical air conditioning system”, International Journal of Energy Research, vol. 30, No. 15, pp. 1251-1263, 2006.
M. A. Abd El-Baky, and M. M. Mohamed, “Heat pipe heat exchanger for heat recovery in air conditioning”, Applied Thermal Engineering, vol. 27, pp. 795-801, 2007.
G. D. Mathur, “Using heat-pipe heat exchangers for reducing high energy costs of treating ventilation air” Proceedings of the 31th Intersociety Energy Conversion Engineering Conference, Washington, DC, USA, vol. 2, pp. 1447-1452, 1996.
Y. H. Yau, and A. S. Tucker, “The performance study of a wet six-row heat pipe heat exchanger operating in tropical buildings”, International Journal of Energy Research, vol. 27, pp. 187-202, 2003.
G. Gan, and S. B. Riffat, “A study of heat-pipe heat recovery for natural ventilation”, Building Services Engineering Research and Technology, vol. 20, pp. 57- 62, 1999.
P. W. Xiao, P. Johnson, and A. Akbarzadeh, “Application of heat pipe heat exchangers to humidity control in air-conditioning systems”, Applied Thermal Engineering, vol. 17, No. 16, pp. 561-568, 1997.
TRNSYS 16, a Transient System Simulation program, the Solar Energy Laboratory, University of Wisconsin- Madison, 2006.
W. K. Ng, M.S. Thesis, “Redesigning of HVAC system to resolve fungus growth and save energy for operating theatres”, University of Malaya, Session 2007/2008.
Y. H. Yau, and W. K. Ng, “A comparison study on energy savings and fungus growth control using heat recovery devices in a modern tropical operating theatre”, Energy Conversation and Management, vol. 52, pp. 1850–1860, 2011.
M. Ahmadzadehtalatapeh, PhD Thesis, “Measurements and Modeling of the Horizontal Heat Pipe Heat Exchangers for Saving Energy and Improving Thermal Comfort in Air-Conditioning Systems in the Tropics”, University of Malaya, Malaysia, 2011