Annual energy consumption calculation model of open-loop lake-source heat pump

Abstract

This article proposes a relatively simple procedure to perform annual hour-by-hour simulations of open-loop lake-source heat pump systems which are composed of two coupled factors including heat pump performance and lake heat transfer. In the first part of the paper, 2-D lake temperature model with eclipse form intake-outlet method is established, and heat pump model is proposed. The governing equations of lake heat transfer and heat pump performance are coupled through the inlet water temperature. Consequently, the equations are solved iteratively with UFD of software Fluent. Then this system is used to heat and cool a three-story 294m2 office. Hourly heating and cooling loads for the building are precalculated with another software DOE2.0 and transferred to the equation solver. And a comparison of annual energy use of lake-source heat pump system with air source heat pump system is presented. Finally, it is shown that SEER of lake-source heat pump system in winter and summer are higher than air-source heat pump system and open loop lake source heat pump systems are more energy efficient than air-source heat pump systems. However, compared with the system without water pump, SEER of open-loop water source heat pump systems with water pump reduces by 17.5%. So, it is necessary to decrease the energy consumption of water pump for higher energy efficiency of open-loop lake source heat pump system.