Techno-economic analysis of high-temperature heat pumps with low-global warming potential refrigerants for upgrading waste heat up to 150 °C

Abstract

This work investigates the techno-economic aspects of high-temperature heat pumps used for waste heat recovery. The heat pump produces heat at a temperature up to 150 °C from heat of below 100 °C based on both single- and two-stage cycles, with the aim of identifying the most cost-effective among various heat sink and heat source temperatures. Refrigerants with low-global warming potential are considered and a validated heat pump model is used to calculate the cycle performance. Then, the equipment cost of the different configurations is calculated as a function of the component parameters and system scale. This approach provides a trade-off between high efficiency versus high cost, in order to identify the most cost-effective configuration at each temperature level. The results show that the specific equipment cost of the heat pump is usually in the range of 150 to 300 EUR/kW, mostly depending on the cycle design and temperature. Moreover, the discounted payback period of industrial installations shows a large scatter, and can even be as short as 3 to 4 years. The overall outcome is that the single-stage cycle with an internal heat exchanger is favoured in terms of economic performance, except with large temperature lifts of over 50 K, in which a two-stage cycle shows superior cost-effectiveness.