Peltier Heat Pump

Due to the ever-improving building physics in new buildings and refurbishments, the specific heating requirement for buildings is being reduced. This increases the percentage of final energy used for water heating. However, low outputs for decentralised use, e.g. in water heating, are only available in rare cases. As a rule, therefore, systems with higher outputs are operated with short running times and low capacity utilisation. There is therefore a lack of technical building systems for heating and cooling for small output ranges (<2 _kWthermal), which have no moving parts and are therefore low-maintenance, have no noise emissions and are therefore also decentralised and, in particular, do not require any climate-relevant refrigerants in the process.

Objectives and methodology:

The aim is to research a building technology system for heating and cooling in the low power range
(<2 _kWthermal), which is characterised by a long service life and low electrical power consumption, which is low-noise, low-maintenance, environmentally friendly (in particular without climate-relevant refrigerants) and can be used with PV characteristics without DC/AC conversion losses. This building technology system should function on the basis of Peltier elements and be suitable for heating and cooling applications and, in particular, for decentralised hot water generation.

The following methods are chosen to achieve the objective:

• Calculation of heat transfer between thermoelectric element and heat exchanger and between the external thermoelectric heat pump/heat exchanger unit and fluid by forced convection based on
  measurements
• Laboratory experiment to test various external thermoelectric heat pump/heat exchanger units for building services applications and to validate the calculation model
• Hardware-in-the-loop simulation in the existing heat pump test rig under realistic loads and simulation of PV variants

Results and findings:

At the end of the project, the result is a researched external thermoelectric heat pump/heat exchanger unit in which thermoelectric elements (Peltier elements) with a heat output <2 _kW can be optimally integrated in terms of heat transfer and can be used for hot water preparation or also for support for heating and cooling purposes (e.g. to create thermal comfort). Due to the imposition of realistic loads and the combined building and system simulation, there are potential applications in building services engineering.