Design and Analysis of Charge‐Reduced Refrigerant Cycles Using R290

Abstract

R290 is one of the most promising refrigerants for heat pumps and cooling processes working in a temperature range of -15 to 70 °C. The nearly neglectable global warming potential and attractive thermodynamic properties allow the design of climate-friendly and efficient refrigeration systems and heat pumps. However, R290 is flammable, and the use of charge-reduced components and designs should be the first central step to reduce safety risks. Whereas the prediction of heat capacity, temperatures and pressure drops are sufficiently precise the prediction of refrigerant charge is not very accurate when using computer-aided design tools. The article presents a method to enhance accuracy for refrigerant cycles with less than 500 g of R290.

Heat Pump Systems in Existing Multifamily Buildings: A Meta‐Analysis of Field Measurement Data Focusing on the Relationship of Temperature and Performance of Heat Pump Systems

“…Propane (R290) is a promising refrigerant with working temperatures of 70 °C and higher. [17] Alternatively, hybrid, bivalent HP systems combine HPs with a secondary heat generator, e.g., a gas boiler, so that temperature and power requirements of existing MFH can be reached. [18] From the literature review, it becomes clear that high temperature requirements are central challenges for retrofitting HP in existing MFH, affecting all three subsystems: 1)all-year high heat source temperatures are desired for an efficient HP operation; 2) the maximum supply temperature of the HP is limited by the design of the refrigerant circuit; and 3) temperature requirements for DHW and SH affect HP performance and the necessity to install a backup heater.…”

“…Propane (R290) is a promising refrigerant with working temperatures of 70 °C and higher. [ 17 ] Alternatively, hybrid, bivalent HP systems combine HPs with a secondary heat generator, e.g., a gas boiler, so that temperature and power requirements of existing MFH can be reached. [ 18 ]…”