FiTNeS - Facade integrated modular Split-heat pump for new buildings and refurbishment

Starting point / motivation

For future buildings - so called nZEBs according to the EPBD - for both new constructions and renovations, efficient and cost-effective heating systems are required that can be operated in a flexible way with a high share of renewable energy (in particular Photovoltaik (PV)/Building integrated Photovoltaik (BIPV)).

The requirement for comfortable indoor climate in summer increases and at the same time, the efficiency in the building sector must be considerably enhanced. Heat pumps are considered among most experts as one of the key technologies in the building sector, however in particular in high-density housing areas source exploitation is strongly limited. Accordingly, the market does not provide real alternatives to apartment gas boiler and electric boilers.

So-called mini-split heat pumps are a promising alternative solution, because these are available due to the extremely high quantities at low prices. Split type heat pumps with low power (in the range below 2.5 kW) can be made compact and cost effective and thus offer new possibilities. However, these split type heat pumps represent a real alternative only if the acceptance for them can be improved by means of improved modularity, design, architectural attractive integration in the building envelope, and reduced sound emissions.

Contents and goals

The goal of FitNeS is the development of modular split heat pumps with compact and silent façade-integrated outdoor units for heating and domestic hot water preparation (and optionally cooling in combination with PV). The outstanding features of the concept are a modular design with a high degree of prefabrication and representing a visually and architectonically attractive, economic and sustainable solution for both new constructions and renovations.

Methods

In the project FitNeS different concepts for façade-integrated outdoor units will be developed and evaluated with regard to design, façade construction, accessibility (for maintenance), building physics, efficiency, etc. on the basis of the technical and non-technical boundary conditions. Diverse concepts for different capacities (e.g. 0.5 kW to 2.5 kW) and accordingly fan types/configurations and evaporator types/configurations will be designed and developed.

The best of these concepts for façade-integrated outdoor units for split heat pumps will be selected and developed in detail and optimized with CAE and CFD tools. Functional models of the façade integrated outdoor unit will be produced and tested for pressure loss and sound emissions.

One of the main development goals is the minimization of sound emissions by means of optimized flow control. Then, one functional model for a split-HP with the optimal façade-integrated outdoor unit will be build and tested in the laboratory with regard to performance and efficiency.

Expected results

With a holistic and systematic approach all aspects of building physics, primary energy saving and efficiency will be evaluated and optimized while the architecturally attractive design remain in the foreground. The verification of compliance with the efficiency and the comfort criteria as well as indoor air quality is carried out by means of extensive dynamic building and system simulation using models validated with the laboratory experiments.

Finally, a functional model will be tested in one flat of a demo building with respect to performance, sound emissions and practical suitability (e.g. maintenance).

Project management

Universität Innsbruck, Institut für Konstruktion und Materialwissenschaften

Projekt- bzw. KooperationspartnerInnen

• Drexel Solarlufttechnik und Lüftungsbau GmbH
• Innsbrucker Immobilien GmbH & CoKG
• element design - Stephan Breier e.U.
• wInterface GmbH
• Drexel und Weiss Energieeffiziente
• Ingenieurbüro Rothbacher GmbH

Fabian Ochs
Technikerstr. 13
A-6020 Innsbruck
Tel.: +43 (512) 507 63603
E-mail: fabian.ochs@uibk.ac.at
Web: https://www.uibk.ac.at/bauphysik/