ExTra - ExergyTrafos for heating and air conditioning through district heating

As a contribution to the reduction of CO2 emissions, the project aims at upgrading existing heating networks by adding new devices, so-called exergy trafos, to the heat-exchanging transfer stations. These are driven by district heat and provide heating and cooling, as well as a reduced return temperature, as a service.

Short Description

Starting point / motivation

The national heating strategy drawn up by the federal and provincial governments plays an important role in achieving the national climate targets (36% reduction in greenhouse gas emissions by 2030 compared with 2005). In the urban sector, the focus is on replacing district heating and cooling, in addition to significantly reducing the energy demand of buildings.

Contents and goals

The project will demonstrate the potential of combining heat, power and cooling services in urban energy networks. The aim is to upgrade the heating network with today's usual supply temperatures by adding new types of exergy trafos to the heat exchanging transfer stations. These are driven by district heat and provide the following services both in summer and winter: cooling (air conditioning), co-generation of heat and cold, and the provision of heat, combined with a reduction of district heating return temperatures to minimize network losses.

Methods

Possible technologies for exergy trafo devices are the absorption technology known from the refrigeration technology (figure 1) as well as the ejector technologies in their novel version (figure 2). If necessary, the service provisions are managed by switchovers.

Ejector technologies in their novel version — Figure 2: Schematics of the novel hot water ejector cycle processes, for cold provision (left), for co-generation of heat and cold (centere) and for heat provision with return temperature reduction (right). Components: AS...separator, AW...heat sink, Eco...economizer, FT...flash tank, FW...district heating, Heiko...heating condenser, HW...heating heat, K...condenser, KW...cooling, SV...jet compressor, V...evaporator, ?...heat sink, if required. (Source: Project ExTra, 2021)

To be able to propose promising (system) solutions as a project result, the following knowledge gaps in must be closed within the project duration:

What are typical demand and consumer profiles of heating and cooling in cities?
What are the performance data of the innovative exergy trafos during seasonal use?
What are the environmental and economic impacts of exergy trafos on future urban heating and cooling networks?

Expected results

In order to solve these questions in the best possible way within the project duration, the core competences of the project consortium will be used. In addition to the collection of consumption profiles, plant simulations with result evaluations are to be carried out.

Based on the project results, the aim is to estimate the potential for a future, concrete integration of absorption and ejector technologies into the energy supply of a Viennese pilot community and to design and implement this in a follow-up project.

Project Partners

Project management

University of Applied Sciences Burgenland GmbH

Project or cooperation partners

Technical office for mechanical engineering and energy technology Dr. Georg Beckmann
Wien Energie GmbH

Contact Address

Prof. (FH) DI Ernst Blümel
Steinamangerstraße 21
A-7423 Pinkafeld
Tel.: +43 5 7705-4130
E-mail: ernst.bluemel@fh-burgenland.at
Web: www.fh-burgenland.at