TY - JOUR
T1 - Performance characteristics of a cascade multi-functional heat pump in the winter season
AU - Boahen, Samuel
AU - Anka, Selorm Kwaku
AU - Lee, Kwang Ho
AU - Choi, Jong Min
N1 - Funding Information:
This work was supported by the National Research Foundation of Korea ( NRF ) grant funded by the Korea government (MSIT) (No. 2019R1A2C2087157 , Artificial neutal network based optimized operating model of building HVAC systems control parameters for improved energy efficiency and reduced operating cost).
Publisher Copyright:
© 2021 Elsevier B.V.
PY - 2021/12/15
Y1 - 2021/12/15
N2 - Cascade multi-functional heat pumps are becoming popular due to their ability to simultaneously provide cooling, heating, and hot water. In this study, the performance characteristics of a water-to-water cascade multi-functional heat pump designed to provide heating, hot water, and simultaneous heating and hot water during the winter season are analyzed according to variation in secondary fluid temperature. The simultaneous heating and hot water cycle was optimized to meet the design heating and hot water capacities by increasing the compressor speeds of the low stage and high stage cycles above those in the heating and hot water cycles. An increase in the outdoor heat exchanger entering water temperature increased the performance of the cascade multi-functional heat pump in all operating modes, while an increase in the indoor heat exchanger entering water temperature resulted in a decrease in the performance of the cascade multi-functional heat pump in all operating modes except the capacity of the hot water cycle in heating-hot water mode. Furthermore, an increase in the hot water entering water temperature resulted in a decrease in the performance of the cascade multi-functional heat pump. The cascade multi-functional heat pump in heating-hot water mode showed similar performance trends as individual heat pumps for space heating and hot water generation and provided much stable hot water capacity at varying outdoor entering water temperature conditions. Cascade multi-functional heat pumps have the potential to provide better energy efficiency at higher heating and hot water loads, and can, therefore, be used for simultaneous space heating and hot water generation in winter seasons.
AB - Cascade multi-functional heat pumps are becoming popular due to their ability to simultaneously provide cooling, heating, and hot water. In this study, the performance characteristics of a water-to-water cascade multi-functional heat pump designed to provide heating, hot water, and simultaneous heating and hot water during the winter season are analyzed according to variation in secondary fluid temperature. The simultaneous heating and hot water cycle was optimized to meet the design heating and hot water capacities by increasing the compressor speeds of the low stage and high stage cycles above those in the heating and hot water cycles. An increase in the outdoor heat exchanger entering water temperature increased the performance of the cascade multi-functional heat pump in all operating modes, while an increase in the indoor heat exchanger entering water temperature resulted in a decrease in the performance of the cascade multi-functional heat pump in all operating modes except the capacity of the hot water cycle in heating-hot water mode. Furthermore, an increase in the hot water entering water temperature resulted in a decrease in the performance of the cascade multi-functional heat pump. The cascade multi-functional heat pump in heating-hot water mode showed similar performance trends as individual heat pumps for space heating and hot water generation and provided much stable hot water capacity at varying outdoor entering water temperature conditions. Cascade multi-functional heat pumps have the potential to provide better energy efficiency at higher heating and hot water loads, and can, therefore, be used for simultaneous space heating and hot water generation in winter seasons.
KW - COP
KW - Capacity
KW - Cascade Multi-Functional Heat Pump
KW - Entering Water Temperature
KW - Winter Season
UR - http://www.scopus.com/inward/record.url?scp=85116514202&partnerID=8YFLogxK
U2 - 10.1016/j.enbuild.2021.111511
DO - 10.1016/j.enbuild.2021.111511
M3 - Article
AN - SCOPUS:85116514202
SN - 0378-7788
VL - 253
JO - Energy and Buildings
JF - Energy and Buildings
M1 - 111511
ER -