Bachelor's thesis Greta KolbCopyright: EBC
In heat pump heating systems, non-halogenated refrigerants will become increasingly important.
The reason is the Montreal Protocol, which sets binding rules for the waiver of ozone-depleting and greenhouse-active substances. Further, the F-gas regulation in force in the EU will reduce the sale of fluorinated refrigerants (F-gases) with a high global warming potential by 79 % with respect to the amount sold in the reference year 2015.
In heat pumps, fluorocarbons are mainly used as refrigerants recently. Due to the artificial shortage and the ensuing increase in price, a transition to alternative refrigerants is required. Therefore, studies of natural refrigerants are executed at the Institute for Energy Efficient Buildings and Indoor Climate of the E.ON Energy Research Center. Hence, a demonstrator test stand of a heat pump applying non-halogenated refrigerants is set up.
Decisive framework conditions for the design of the test stand are the maximum heating load and the alternatively used refrigerant. Based on the normative standard DIN EN 12831, the maximum heating load of a single family house is determined. Various insulation regulations since 1984 have been taken into account. By a simulation model of a detached house, a maximum heating load to the safe side of 10 kW for buildings with a low insulation standard was calculated.
Regarding the selection of suitable refrigerants, thermodynamic requirements in compression heat pumps are defined and criteria are established. Especially propane convinces as an alternative hydrocarbon refrigerant despite its flammability due to its suitable thermodynamic behavior.
With respect to literature review, a test stand is developed. A market research faces propane compressors.
The compressors are evaluated by developing cost-benefit dependencies. Capital-related, operational-related and demand-related costs will be investigated over the use phase of a heat pump according to the VDI guideline 2067. A critical evaluation is based on the COP. The best performing compressor is compared to a conventional gas fired boiler and the options for action is be discussed.