24 June 2014


A new air-water heat pump has been developed by Bosch Thermotechnology with the goal of collectively satisfying customer, installer and newest legislative requirements. In a
first step, a multi-dimensional noise, size, weight and heat transfer optimization study was performed to size the hardware components. This provided the foundations for a much better performing heat pump that was more compact and lighter compared to previous units. New materials and components, an intensive study on the fan, air chamber and evaporator
optimizing noise, air flow and size lead to a significant improvement. In a second step, an optimized heat pump control algorithm was developed to maximize the inverter driven
compressor capability in terms of efficiency and operating envelope by minimizing reliance on the electric heating rod and on/off cycling with a more continuous heat supply. Other key
features include novel inverter cooling and full reversibility for cooling on warmer days showing the customer comfort being in focus. The contribution of all steps will produce a high European Ecolabel score and be very good compared to market level. This paper describes the optimization methodologies and their outcomes. Also described are the various
thermodynamic, CFD numerical calculations along with measurements undertaken during development leading to the final design and results.