Modeling and application of direct-expansion solar-assisted heat pump for water heating in subtropical Hong Kong

The calibration and validation of a model for predicting the performance of gas-fired tankless water heaters in domestic hot water applications

“…As an example, applications where solar thermal collectors are used to provide DHW for residential applications is an active area of [13][14][15][16][17][18][19][20][21][22]). In order to assess the energy savings of this type of system, a well-justified model of a conventional method for producing DHW is required for comparison.…”

Mathematical Thermal Modelling of a Direct-Expansion Solar-Assisted Heat Pump Using Multi-Objective Optimization Based on the Energy Demand

“…Alternatively, several authors developed and proposed mathematical models of the system employing a more robust approach where every process of the heat pump cycle was modelled separately and then connected to simulate and quantify the performance of the HP in terms of COP and collector efficiency such as Sterling et al [28], Li et al [29], Çaglar et al [30], Kokila et al [31] and Gorozabel-Chata et al [32], in terms of exergy destruction and second law of thermodynamics, by Atmaca et al [33] and Torres-Reyes et al [34] respectively, and based on worktime and flow resistance in the collectors such as the one proposed by Chyng et al [35]. One particular study is the one published by Chow et al [36] where they set out a comprehensive model centered on the effect the atmospheric conditions have on the yearly performance of the heat pump, employing a 25 years period database of the typical meteorological months.…”

Experimental investigation of a solar driven direct-expansion heat pump system employing the novel PV/micro-channels-evaporator modules

“…Huang et al [13] reported the performance of DX-SAHP under the frosting conditions, indicating that the solar irradiance of around 100 W/m 2 could prevent formation of the frosting when the ambient temperature is above À3°C and the relative humidity is around 70%. Chow et al [14] presented the theoretical study into a solar-assisted direct-expansion heat pump for water heating in a subtropical weather condition, indicating that the system can achieve an annual average coefficient of performance (COP) of 6.46, which is much better than that of the conventional heat pump systems.…”