Indoor R-290 Heat Pump Safety Concepts: Development, Measurement and Evaluation
As part of the LCR290 project, R-290 heat pump solutions for multi-family houses were planned, simulated, tested, and evaluated. The project reports to an advisory board representing the housing industry as well as the heat pump manufacturing industry. One of the main areas of attention are safety concepts for indoor brine-to-water heat pump installations. As part of the project, a heat pump demonstrator was built to test different safety concepts by releasing R-290 into the enclosure located in a test room. The demonstrator represents a 30kW heating capacity heat pump with 800g refrigerant charge. The test room has controlled and varied air exchanges rates starting at around 0 up to 17. The test facilities enable the use of safety concepts without exchange to the ambient air and concepts with R-290 exhaust to the ambient. The developing R-290 concentrations in and around the heat pump enclosure were measured using concentration sensors. The measurement method used for testing the concentration includes the variation of (i) leakage mass flow rate, (ii) leakage position, (iii) enclosure tightness, (iv) room air exchange ratio and (v) enclosure air exchange ratio. This contribution presents the measurement methodology used. Different safety concepts have been tested, using the adaptive demonstrator. The results of a selection of these tests, resulting in time developing propane concentration measurements at multiple locations, are shown. The results have tangible value in quantitative risk assessment and are good candidates for improving existing safety concepts as well as the evaluation methods of R-290 outflow measurements.