CHALLENGES IN HEAT-PUMPING TECHNOLOGIES
There are many types of applications of Heat Pumping Systems and Equipments. Most notably heat pumps for climate control – heating as well as cooling – in buildings. But the concept of heat pumping also includes refrigeration for traditional uses like for the cold chain for food but also for medical applications and low temperature applications in cryogenics. During the last two decades there has been a technology shift with a transition from using CFC and HCFC to new refrigerants like HFC and “natural” refrigerants. This transition has proceeded in slightly different direction and different emphasis in different parts of the world. It has also provoked a renewed interest in different cycles. Advanced designs of buildings will reduce the heating demand. Heating of tap water will be a substantial load and also the demand for cooling in summertime. Different climatic conditions give priority to different choices. A most important challenge is to reduce energy demand as well as demand for peak power. Efficient heat pumping systems require careful choices of cycles and designs of heat sources/sinks as well as heat exchangers with small temperature differences.