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DAKTris – Dynamic Operational Behaviour of Absorption Chillers in Trigeneration Systems

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Project leader University Innsbruck: Daniel Neyer

Projekt members: Jacqueline Neyer, Alexander Thür, Norbert Hauer

 Project partners

Funding Agency: BMVIT, Haus der Zukunft Plus, 4th call (Projekt Nr. 840650)

Project Period: 01.07.2013 - 30.06.2016

One possibility to provide multifunctional buildings and urban settlements with heat, cold and electricity is the use of so called trigeneration systems. First results of relevant projects (e.g. PolySMART) show a significant potential for small capacity systems and the necessary steps toward economical and primary energy efficiency. Main challenges are the adjustment of the main components, the combined heat and power unit (CHP) and the absorption chiller, as well as the design of the overall system (user profile, hydraulics, control strategy, ...).

Absorptionskältemaschine mit BHKW

Up to now trigeneration systems are built up with standard absorption chillers. Most of these chillers are not designed for such operation conditions. When adapting the chiller with respect to higher generation temperatures and dynamic boundary conditions by means of the optimization of the internal circuit the requirements for a successful and efficient system solution can be fulfilled. Increasing the use of rejected heat from the CHP unit (e.g. during summer time) results in higher hours of operation and thus in higher electricity production and economic feasibility.

By means of market, economic and primary energy considerations as well as dynamic system simulations, profiles for multifunctional buildings (residential and non-residential use) will be set up. Corresponding to these profiles system configurations (with/without storage, choice of CHP Unit, …) including control strategies will be defined and analyzed in the project steps.

After the adaption of the chiller to the specific boundary conditions the different system configurations will be analyzed in hardware-in-the-loop measurements. In these lab tests the system performance can be measured and mapped under realistic dynamic conditions. Using this method early stage analyses of the systems can be carried out, leading to reduced costs and higher success rates in the implementation.

Additionally statements concerning economic and primary energy efficiency can be determined and the systems can be optimized respectively.

Finally an economic and primary energy efficient operation can only be guaranteed with an adequate choice and adjustment of the single components. Thus, a significant contribution to the reduction or even avoidance (if using biomass-fired CHP units) of greenhouse gas emissions of the building sector can be achieved.