Abstract: Electric vehicle heat pumps are drawing more and more attention due to their energy-saving and high efficiency designs. Some problems remain, however, in the usage of the heat pumps in electric vehicles, such as a drainage problem regarding the external heat exchangers while in heat pump mode, and the decrease in heating performance when operated in a cold climate. In this article, an...

A heat pump system is constructed tO evaluate the performance and the heat transfer characteristics. Mixtures of R22/Rl42b are adopted in the heat pump. The heat transfer in the evaporator and the overall perfomance arc measured and analyzed in terms of the compositions and the flow rate of the refrigerants. The evaporator consists of counter~currem concentric circular tubes. Possibility of cap...

The heating capacity and coefficient of performance (COP) of conventional air-source heat pumps decreases towards lower ambient temperatures. In addition, high discharge temperature at the compressor discharge might limit the operation of the heat pump at very low ambient temperatures. Oil injected into the compression chamber at the beginning of the compression process can absorb part of the h...

Despite continual development over more than two centuries there is still great scope for significant in the realms of mechanical cooling and heating. This paper reviews nature historical identifies key motivations technical development. It seeks to highlight where greatest need future this ubiquitous technology. The story refrigeration dominated by choices made with regard working fluid used s...

In district heating stations, the heat carrier is circulated between the energy source and consumers by a pumping system. Fluid handling systems, such as pumping systems, are responsible for a significant portion of the total electrical energy use. Significant opportunities exist to reduce pumping energy through smart design, retrofitting, and operating practices. Most existing systems requirin...

To minimize the total energy consumption of a cooling tower-assisted heat pump (CTAHP) system in cooling mode, a model-based control strategy with hybrid optimization algorithm for the system is presented in this paper. An existing experimental device, which mainly contains a closed wet cooling tower with counter flow construction, a condenser water loop and a water-to-water heat pump unit, is ...