ISSN 1923-8460[PRINT] ISSN 1923-8479[ONLINE] www.cscanada.net www.cscanada.org Energy Science and Technology Vol. 3, No. 2, 2012, pp. 84-92 DOI:10.3968/j.est.1923847920120302.397 84 Copyright © Canadian Research & Development Center of Sciences and Cultures A TRNSYS Simulation Case Study on Utilization of Heat Pump For both Heating and Cooling S.M. Al-Zahrani [a] ; F.L. Tan [b],* ; F.H. Choo [c] [a] King Saud University, Chemical Engineering Department, P.O. Box 800, Riyadh 11421, Saudi Arabia. [b] Nanyang Technological University, School of Mechanical and Aerospace Engineering, 50 Nanyang Avenue, Singapore. [c] Nanyang Technological University, School of Electrical and Electronics Engineering, 50 Nanyang Avenue, Singapore. *Corresponding author. Funded by King Saud University (KSU) and Nanyang Technological University (ERI@N) Received 20 April 2012; accepted 14 May 2012 Abstract This paper presents a TRNSYS simulation case study on the integration of a heat pump into a hot water and cold water storage systems for the purpose of providing heating and cooling to a residential home or offce building in a tropical climate. The motivation is to utilize waste heat rejected by the heat pump.The heat pump is integrated with two water storage tanks. One is the cold water tank where heat is extracted by the heat pump and the other is the hot water which stores the heat rejected by the heat pump. The cold water tank provides cooling water for air conditioning to the building. The hot water tank is used for daily usage like bathing and washing. The sizing of the two storage tanks and the balancing of the heat transfer between the two tanks are important design factors to maintain suitable temperatures in the storage tanks. The paper discusses the performance of the integrated system under different operational modes and the effects of each storage tank size on the performance. Key words: Heat pump; Heating; Cooling; TRNSYS; Simulation; Air conditioning Al-Zahrani, S.M., Tan, F.L., & Choo, F.H. (2012). A TRNSYS Simulation Case Study on Utilization of Heat Pump forboth Heating and Cooling. Energy Science and Technology , 3 (2), 84-92. Available from: URL: http://www.cscanada.net/index. php/est/article/view/10.3968/j.est.1923847920120302.397 DOI: http://dx.doi.org/10.3968/j.est.1923847920120302.397 Nomenclature Q c Heat absorbed from the cold tank (kJ/hr) Q h Heat rejected to hot tank (kJ/hr) γ c Output signal from cold tank differential controller γ h T a V a V hw Output signal from hot tank differential controller Ambient temperature (°C) Flow rate of ambient air cooled by cooling coil and supplied to space (L/hr) Flow rate of hot water used for daily usage (L/hr) INTRODUCTION Increase of oil price and its depletion along with globalwarming have pushed various researches to study and utilize alternative energy available to meet mankind needs. This resulted in the current vast development of various clean energy industries in various countries. In addition of fnding new alternative energy to meet energy consumption and demand, researches are also looking into ways to maximize the usage of low quality heat rejected by the equipment to be used for various applications such as cooling or heating.The utilization efficiency of the energy can be increased through the use of waste heat instead of rejecting it to ambient. One solution is the use of heat pump in a residential home or offce building for both cooling and heating. A heat pump transfers heat energy from lower- temperature space to higher-temperature space, through the input of electrical energy. Baek, Shin & Yoon (2005) studied and analyzed the application of heat pump system in Korea, for supplying hot water using heat from sauna waste water as the heat source. They found that average annual COP was 4.5 to 5, which is higher than heat pump with ambient air heat source and that it can provide 90% of the instant hot water load. In addition, heat pump can also be used for both cooling and heating application, depending on the needs.