Critical review of heat pump prototype operation and required modications
Creators: name: Alireza Zendehboudi
name: Schubert, Maike
name: Peña, Xabier
name: Gerber, Raphael
Publisher: name: Zenodo
Year: 2022
Subjects: Heat pump
R744 (CO2)
R290 (propane)
ice slurry

description: TRI-HP EU project is aiming to develop trigeneration integrated solutions that combine heating, cooling and electricity<br> generation, based on heat pumps running with natural refrigerants and using multiple renewable energy<br> sources.<br> This deliverable presents the experimental performance evaluations of the R744-ice heat pump, R290-ice heat<br> pump, and R290-dual source heat pump. The R744-ice heat pump includes a rotary compressor coupled to an<br> inverter, the tri-partite brazed plate gas cooler, an evaporator, an internal heat exchanger, an ejector, a throttling<br> valve, and a liquid separator. The heat pump unit is designed with a capacity of 10 kW, 8 kW, and 10 kW under<br> only domestic hot water, only space heating, and simultaneous domestic hot water and space heating modes to<br> provide the tap water heating and space heating water up to 70 °C and 35 °C, respectively. The rst R290-ice heat<br> pump prototype is designed with a capacity of 10 kW and consists of a scroll compressor with inverter, two plate<br> heat exchangers in the heat sink side (desuperheater and condenser), an evaporator, an internal heat exchanger,<br> and several expansion valves. A 10 kW R290-dual source heat pump is designed and manufactured to use both air<br> and/or brine coming from geothermal boreholes as heat source/sink, allowing to test this unit under heating and<br> cooling working modes.<br> The R744-ice heat pump and R290-ice heat pump are studied at a steady state for only space heating operation,<br> only domestic hot water operation, and simultaneous domestic hot water and space heating operation. The R290-<br> dual source heat pump is investigated under heating and cooling conditions applying air and/or water as the heat<br> source/sink. The effects of different operating parameters on the overall coefcient of performance, heat duty,<br> and compressor energy consumption are analyzed in detail. The experimental results of the tested heat pumps<br> show promising performances. The COP of R290-ice heat pump for space heating temperature 30/35 °C ranges<br> between 4.4 and 5.4. However, the COP of the unit for domestic hot water with a set temperature of 65 °C drops<br> to between 2.5 and 2.8. This is where the CO2-ice heat pump shows good results for high domestic hot water<br> demand. In domestic hot water mode, the COP varies between 3.6 and 4.3 for set temperatures of 55 °C to 65 °C.<br> The delivered heating capacity of the R290-dual source heat pump is slightly lower than the requirements under<br> the design conditions. The coefficient of performance varies between 3.2 and 3.6, depending on the operating<br> mode.<br> After the performance evaluations of these prototypes, this deliverable provides and describes the limitations of<br> the designed systems. It provides recommendations for the performance improvements to be implemented in the<br> second experimental campaign.