Waste Heat Recovery Using A Miniaturized Heat Pump at Mobile Base Stations
The widespread 5G telecommunication base stations (TBS) represent a widely distributed waste heat resource in urban areas which is yet unexploited. The low-grade waste heat at 30–45°C within TBS cabinets coincides with year-round building heat demands for Domestic Hot Water (DHW) circulation systems. The need for temperature upgrade and strict volume constraints of TBS cabinets create a critical research and development need for miniaturized, cabinet-integrated heat pump (HP) solutions. This paper presents a comprehensive "concept-to-deployment" investigation of such a waste heat recovery system based on a miniaturized heat pump. In this paper, we designed and prototyped a novel, cabinet-integrated "miniaturized heat pump door" using R600a charge below 150 g. Through a dedicated test rig, we performed experimental characterization of HP performance and used experimental data to validate a numerical thermodynamic (IMST-ART) model of the HP. Experimental results show that the prototype successfully upgraded cabinet’s warm air at 37 °C to DHW at 55 °C with a total COP of 3.1 and waste heat recovery ratio of 85%. We used the validated HP model to investigate improved evaporator alternatives with denser fins and a microchannel heat exchanger. Through combined thermodynamic and heat transfer simulation, we identified an HP and cabinet renovation delivering 1.45 kW of heat to DHW systems while ensuring critical electronics hotspot junction temperatures remained safely below 60°C. The techno-economic analysis of the integrated system shows that the heating costs can be saved by 858 €/year through reduced district heating demands for DHW production, considering the current energy prices in Sweden. This saving justifies a capital investment of 10,000 € for seven-year operation while HP components cost only 2,000 € at our laboratory. The experimental and simulation results in this paper validate a novel and viable waste heat recovery pathway to valorize waste heat from telecommunication infrastructure.