Propane warmth pumps for indoor use in single-family houses at the moment are one step nearer to commercialization. Fraunhofer ISE in Germany has efficiently developed a mannequin of a warmth pump refrigeration circuit utilizing lower than 150 g of propane.
“Many warmth pump producers supply propane warmth pumps however often for outside set up solely, because the refrigerant is topic to intensive security laws for in-door use on account of its flammability,” mentioned Fraunhofer ISE in an announcement. “If a warmth pump in a single-family dwelling with a typical 5 kW to 10 kW energy exceeds the prescribed most 150 gram refrigerant cost, then it may well solely be put in by making of extra security measures.”
Probably the greatest outcomes of the Low Cost 150 g (LC150) challenge is a brine warmth pump with a heating capability of 11.4 kW utilizing solely 146 g of propane, making it appropriate for indoor use with out -through many security precautions. The unit’s refrigerant cost is 12.8 g/kW, which is about one-fifth of the propane cost in commercially out there methods, in line with the German analysis institute.
“The purpose of the challenge is to develop an nearly market-ready warmth pump module that makes use of the climate-friendly refrigerant propane, doesn’t exceed the 150-gram restrict for indoor use, and nonetheless supplies enough warmth for single-family houses,” mentioned Dr. Lena Schnabel, head of the heating and cooling division at Fraunhofer ISE. “Now we have achieved this purpose in cooperation with our industrial companions and offered them with the instruments to create a ready-made warmth pump.”
The analysis consortium has constructed, measured, evaluated, and optimized greater than 20 totally different combos of warmth exchangers and compressors. One of many key elements in lowering the required quantity of propane is the usage of an asymmetrical plate warmth exchanger. Different causes embrace utilizing much less oil within the compressor and shortening the size of the tubes.
In October 2022, Fraunhofer ISE developed a warmth pump with a heating capability of 12.8 kW utilizing solely 124 grams of propane. Nonetheless, its refrigeration circuit isn’t appropriate for commercialization as a result of it makes use of a semi-hermeneutic automated compressor that can’t function for lengthy sufficient.
The analysis institute now desires to develop low-charge propane warmth pumps to be used in multi-family houses, as a part of the LC290 challenge that runs till June 30, 2025. The consortium goals to develop warmth pump options for ground heating methods, indoor central heating. methods, and high-performance, outside, warmth pumps.
The initiatives are funded by the German Federal Ministry for Financial Affairs and Local weather Motion.