Modeling an Alternate Operational Ground Source Heat Pump for Combined Space Heating and Domestic Hot Water Power Sizing

Abstract

This study developed an alternate operational control system for ground source heat pumps (GSHP), which was applied to determine combined space heating and domestic hot water (DHW) power equations at design temperature. A domestic GSHP with an alternate control system was implemented in a whole building simulation model following the heat deficiency for space heating based on degree minute counting. A simulated GSHP system with 200 L storage tank resulted in 13%–26% power reduction compared to the calculation of the same system with existing European standards, which required separate space heating and DHW power calculation. The periodic operation utilized the thermal mass of the building with the same effect in the case of light and heavy-weight building because of the very short cycle of 30 min. Room temperatures dropped during the DHW heating cycle but kept within comfort range. The developed equations predict the total power as a function of occupancy, peak and average DHW consumption with variations of 0%–2.2% compared to the simulated results. DHW heating added the total power in modern low energy buildings by 21%–41% and 13%–26% at design temperatures of −15 °C and −26 °C, respectively. Internal heat gains reduced the power so that the reduction effect compensated the effect of DHW heating in the case of a house occupied by three people. The equations could be used for power sizing of any heat pump types, which has alternate operation principle and hydronic heating system.

Renovation Results of Finnish Single-Family Renovation Subsidies: Oil Boiler Replacement with Heat Pumps

“…The performance of GSHP and AWHP in renovated residential buildings has already been studied in many scientific papers. The results of this study confirm the better functioning of the GSHP that is shown by D'Agostino et al [42], Fadejev et al [46] and Ahmed et al [40]. Properly sized heat pump systems with energy piles can have overall system SCOP values higher than 4.5, while some case studies have reported only half of such SCOP values.…”

“…Altogether, three occupants were considered as the average number of inhabitants in the building. The consumption profile of domestic hot water was taken from the study of domestic hot water use in Finnish residential buildings [39,40]. The calculations did not include the electrical heater of the sauna and other electrical appliances that are not specified in Finnish energy efficiency calculation rules.…”

Systematic Renovation Design of Surface Water Source Heat Pump for a Hot Spring Center Based on Thermodynamic Analysis

“…So far, the application and renovation of WHSP mainly concentrate on the optimization of heat exchangers, water pumps, the overall system, and economic frictional head loss. Most mathematical models are built to optimize the following items: optimization parameters, control forms, costs, and feasibility of investment and construction [22][23][24][25][26][27][28]. For the surface WSHP system, there should exist an optimal operating condition for the chilled water circulating system, cooling water circulating system, refrigerant circulating system and transmission pipes, and heat exchangers, under which the system could operate with the minimum energy consumption.…”