HEAVEN – Modulating Brine Heat Pump with Multiple-Source System and Decentralized Ventilation Equipment

Duration: 01/2018 - 12/2020
Contracting Authority/ Sponsors:
Bundesministerium für Wirtschaft und Energie (BMWi), Projektträger Jülich (PTJ)
Project Partners: Viessmann Werke Allendorf GmbH
Website: LowEx-Bestand
Project Focus:
Air inlet of an air/brine heat exchanger with measurement technology during experimental studies on the frosting and defrosting behavior
© Fraunhofer ISE / Photo: Tobias Helling
Air inlet of an air/brine heat exchanger with measurement technology during experimental studies on the frosting and defrosting behavior.

The project network LowEx Concepts for the Heat Supply of Existing Multi-Family Houses (LowEx-Bestand) comprehensively analyzes, develops and demonstrates solutions for the application of electric and gas heat pumps, heat transfer systems and ventilation systems in energetically renovated multi-family houses. One of this network’s technology projects is the HEAVEN (HEAting and VENtilation) project. Its three development goals are to develop a power-modulating brine heat pump with combined use of ground and outside air heat sources (WP1), to optimize the control of decentralized ventilation devices for a single room or an entire apartment and establish a novel evaluation method (WP2) and to develop a functional model for an energy-efficient and quiet decentralized ventilation equipment with a coaxial heat exchanger (WP3).

3D design plan of the purging air test stand for evaluating the energy efficiency of decentralized ventilation equipment at Fraunhofer ISE
© Fraunhofer ISE
3D design plan of the purging air test stand for evaluating the energy efficiency of decentralized ventilation equipment at Fraunhofer ISE
First prototype of the 3D-printed coaxial heat exchanger
© Fraunhofer ISE
First prototype of the 3D-printed coaxial heat exchanger.
Cut of the coaxial heat exchanger
© Fraunhofer ISE
Cut of the coaxial heat exchanger.

Work package 1: Modulating brine heat pump and combined heat sources

In part as a response to limited usable space in urban settings, trends are showing a tendency toward using outside air as a heat source. Since this is relatively inefficient and subject to the German statutory regulation on noise pollution (TA Lärm), WP1 aims to combine the benefits of both outside air and ground as heat sources.

Design and operations strategies will be developed using model-based analyses. The objective is to optimize the average heat source temperature and to enable an energy exchange between heat sources (regeneration, thawing). Laboratory measurements of the new heat source hydraulics and control as well as frosting and defrosting behavior of the air/brine heat exchanger are set to precede the field test in an existing multi-family house.

 

Work package 2: Optimizing and evaluating components of an apartment ventilation system

A decentralized residential ventilation system can play a key role in the renovation of multi-family houses (including those without ducting). However, no suitable methods have been found for the combined energetic and ventilation efficiency evaluation of such equipment.

WP2 is therefore focused on developing a suitable method for evaluating decentralized ventilation equipment in residential settings. This method must encapsulate the evaluation of ventilation efficiency, energy efficiency and comfort, both in the lab and in the field.

Innovative controls for this equipment will also be developed and tested both in simulations and in the field during measurement campaigns.

 

Work package 3: Decentralized ventilation equipment with coaxial heat exchanger and energy-efficient axial fans

Decentralized ventilation equipment is constantly subject to new requirements regarding properties such as compactness, heat recovery and noise development. At the same time, the demand for decentralized energy-efficient residential ventilation systems is also increasing. Researchers expect that turning to a coaxial heat exchanger will satisfy these requirements.

The goal of WP3 is therefore to develop a functional model based on a coaxial heat exchanger. In contrast to the decentralized ventilation equipment used previously, this technology offers the advantages of continuous operation, which minimizes noise pollution, simpler installation with only one core borehole and scalability thanks to innovative manufacturing processes.