For the environmentally aware, natural refrigerant such as CO2 is recommended and pursued by researchers for refrigerators. In this paper, a transcritical CO2 heat pump system was set up to investigate the influence of refrigerant charge on the performance of a small-sized heat pump water heater. The transcritical CO2 heat pump system was composed of a rotary compressor, a tube-in-tube evaporat...

The heating capacity and coefficient of performance (COP) of conventional air-source heat pumps decreases towards lower ambient temperatures. Additionally, the heat pump stops running at very low ambient temperatures due to the high discharge temperature at the outlet of the compressor. Oil injected into the compression chamber absorbs the heat generated during the compression process and thus,...

A geothermal heat exchanger system is mathematically quantified, and simulated and modeled to understand heat transfixion and strata deformation caused by groundwater exploitation via groundwater heat pump systems. This is done to determine the requirements and parameters governing the development of shallow geothermal energy in an efficient and safe manner. The model takes into account the gro...

A vertical geothermal probe consists of two or four polyethylene tubes U-shaped, used for circulating the coolant between the heat pump and the ground. It is installed in a deep borehole and sealed in a special grout, a kind of liquid cement, used to seal the borehole, and avoid the presence of air bags between the probe and the ground. Moreover, the grout provides a heat transfer medium betwee...

Simultaneous production of fresh water and refrigeration are often required, e.g. in warm-climate water-deficient regions, and this study is a proposal and analysis of an efficient way of producing both of them by consuming mainly low-grade heat. After introducing the configuration choice methodology, a combined refrigeration and water system, ARHP-MEE (Absorption Refrigeration Heat Pump and Mu...

In this paper, a dynamic heat exchanger model that unifies the frosting and defrosting analyses is presented. A novel scheme is proposed to solve the air flow redistribution due to non-uniform frost blockage. Unlike the existing defrost models which separate analysis for tubes and fins, the proposed defrost model unifies the analysis to maintain model consistency. The first-principles based fro...

A ground source heat pump connected to a domestic hydronic heating network is studied to be driven with the minimum electric power. The hypothesis is to decrease the forward temperature to the extent that one of the hydronic heaters work at full capacity. A less forward temperature would result in a dramatic temperature drop in the room with saturated actuator. The optimization hypothesis is in...

Simultaneous production of fresh water and refrigeration are often required, e.g. in warm-climate waterdeficient regions, and this study is a proposal and analysis of an efficient way of producing both of them by consuming mainly low-grade heat. After introducing the configuration choice methodology, a combined refrigeration and water system, ARHP–MEE (absorption refrigeration heat pump and mul...

The development of the ground source heat pump (GSHP) has been limited by its relatively weak capacity of heat transfer, so the GSHP system normally requires large-scale heat exchangers and higher initial capital investment. Nevertheless, its potential for application of earth energy and friendly environmental protection has drawn a great attention from the international societies and a lot of ...

Thermoelectric cooling and micro-power generation from waste heat within a standard desktop computer has been demonstrated. A thermoelectric test system has been designed and constructed, with typical test results presented for thermoelectric cooling and micro-power generation when the computer is executing a number of different applications. A thermoelectricmodule, operating as a heat pump,