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charging volume, the higher the relative reduction in the COP for the integrated CO2 heat pump unit. In addition, the inlet water flow during the tapping period will lead to inevitable mixing of DHW and city water, and further increase in the thermodynamic losses Table 7.1 Charging Period [h] 0.5 1.0 2.0 4.0 Estimated COP and relative COP reduction (∆COP) for the prototype CO2 heat pump, when including the impact of the conductive heat transfer inside the DHW tank. 7 – Discussion and Analysis Initial Temp. [oC] Combined Mode DHW Mode Charging COP ∆COP Charging COP ∆COP Volume [l] Volume [l] 60/10 60/10 60/10 69 3.46 -11% 138 3.53 -7% 60/10 138 3.64 -9% 276 3.61 -5% 17 34 2.98 -23% 3.23 -17% 34 3.32 -13% 69 3.42 -10% Application of a Movable Insulating Plate One possible way to reduce internal conductive heat transfer and eliminate the mixing in cylindrical single-shell DHW tanks is to separate the hot water and the city water volumes by means of a movable insulating plate. The experiments (Section 5.2.2, Testing of a Movable Insulating Plate) demonstrated that a 50 mm XPS plate will contribute to a reduction in the heat transfer rate between the reservoirs by roughly 80%. The functio- nality of the movable plate was completely satisfactory at atmospheric test conditions, but it was impossible to test the plate at pressurized conditions (4 to 6 bar) since the DHW tank was made of polycarbonate plates. How- ever, according to theory (Section 3.3.4, Application of a Movable Insu- lating Plate Inside the DHW Tank), pressurized operating conditions should not affect the functionality of the plate, since the small gap between the plate and the tank wall will lead to a uniform static pressure in the tank. The concept of a movable insulating plate for reduction of the thermo- dynamic losses in single-shell cylindrical DHW tanks seems promising, but definite conclusions regarding the optimum design, functionality and thermal performance can only be drawn after full-scale testing has been carried out at real operating conditions in an unvented DHW tank. First- costs as well as the long-term reliability of the insulating plate are also important issues that need to be further addressed. 213PDF Image | Residential CO2 Heat Pump System for Combined
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CO2 Organic Rankine Cycle Experimenter Platform The supercritical CO2 phase change system is both a heat pump and organic rankine cycle which can be used for those purposes and as a supercritical extractor for advanced subcritical and supercritical extraction technology. Uses include producing nanoparticles, precious metal CO2 extraction, lithium battery recycling, and other applications... More Info
Heat Pumps CO2 ORC Heat Pump System Platform More Info
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