Under the framework of the Investor Confidence Project, the waste heat of two fast cooling plants are used (by means of heat exchangers in the hot gas tube with partially condensation) to support the heating demand of three ventilation systems located in the immediate vicinity in the engineering room at the top floor of the facility.
- Company: GMS GOURMET GmbH
- Location: Vienna, Austria
- 190-200 tons of annual CO2 savings
- Annual energy savings of 635 MWh in natural gas and 135 MWh in electricity
Improving efficiency and standards
GOURMET is the market leader in community catering in Austria and has 1,500 employees. It caters to kindergartens, schools, offices, homes, care centres, hospitals and other organizations and acts as a caterer and private label producer.
“As a responsible company we treat the earth’s natural resources with care and continuously work on improving efficiency and standards.”
— Hannes Hasibar, Managing Director GOURMET
The company has worked for years on increasing energy efficiency which not only brings environmental benefits but also a reduction in expenses. In order to meet their 2022 goal of reducing energy use by 3%, established in their business strategy, a waste heat of two fast cooling plants (by means of heat exchangers in the hot gas tube with partially condensation) was installed to support the heating demand of three ventilation systems located in the immediate vicinity in the engineering room at the top floor of the facility. This is a rather straightforward technology which functions by putting the waste heat through a heat exchanger and then directing it towards the mentioned ventilation systems. In addition, the implementation of this Energy Conservation Measure (ECM) also allows for the reduction of the electricity demand of the multi-compressor refrigeration systems as their Energy Efficiency Ratio (EER) is increased during the summer which can be regarded as an additional benefit.
Ensuring the quality of the project
“The application of ICP in our industry projects gives the project owner even more robust, independently verified savings calculations and an additional level of quality assurance. Moreover, it puts more focus on proper project implementation in addition to project development.”
— Christian Schuetzenhofer, Managing Director, Denkstatt & Enertec
The implementation of the ECM at GOURMET was executed under the Investor Confidence Project (ICP), which “reduces transaction costs by assembling existing standards and practices into a transparent process that promotes efficient markets by increasing confidence in energy efficiency outcomes”. Under their framework, energy efficiency projects are delivered ensuring high quality and safe returns by standardizing how they are developed, documented and measured.
As mentioned, the first step in the execution of the project under the IPC framework was the establishment of baseline consumption, to later on calculate the potential energy savings. The process followed is described below:
Establishment of the baseline
To calculate the natural gas savings, the natural gas consumption of the facility was chosen as baseline. To calculate the electricity savings, the electricity consumption of a submeter covering the two fast cooling plants was chosen as baseline. In both cases, full year data was used.
A correlation analysis was performed for the natural gas consumption for heating degree hours (data from the weather station at the facility) and weekly production rates (tonnes/week). In the case of electricity consumption for the two fast cooling plants, a correlation analysis was performed for cooling degree hours and the weekly production rates.
Energy demand of the ventilation systems was simulated on an hourly basis dependent on the outside air temperature of the baseline period. Waste heat “production” and electricity consumption by the NK and TK fast cooling plants was calculated based on the hourly data from the building control system on the runtime of the multi-compressor refrigeration systems. Two different situations (winter and summer) with different EERs were assumed.
Calculation of the savings
To calculate the expected natural gas savings, the heat demand of the affected ventilation systems was simulated on an hourly basis. As there already were waste heat recoveries systems implemented to support the heating demand of the ventilation systems, the baseline waste heat recovery from these systems was subtracted from the general heating demand.
In the next step of the calculations, the possible utilization of the waste heat theoretically available from the TK multi-compressor refrigeration system was simulated. Afterwards the same was done for the NK multi-compressor refrigeration system. For electricity savings, after the implementation of the measure it was assumed that the EER is the same during the whole year. Electricity savings were calculated by subtracting the new simulated electricity demand from the baseline simulated electricity demand.
Design, construction and verification
As established by the ICP framework, their verification methodology utilises an Operational Performance Verification (OPV) approach to ensure that the implemented ECM was installed correctly and is capable of achieving the predicted energy savings. OPV is a targeted process that focuses specifically on the ECMs involved in the Project and differs from traditional Commissioning which typically refers to whole facility optimisation.
Measurement and verification
Through an adjusted baseline an assessment is conducted on what the baseline energy use would have been if the ECM had never been installed, under the same set of post-retrofit conditions. Realised savings are then determined by comparing this adjusted pre-retrofit baseline energy use model with the actual energy use of the installation. The energy savings are verified through comparison of the pre- and post-retrofit energy performance of the system.
The project has predicted annual energy savings of 635 MWh in natural gas and 135 MWh in electricity and it was developed by Denkstatt & Enertec who provided baselining and energy savings calculations and also developed the Operational Performance Verification (OPV), Operations, Maintenance & Monitoring (OM&M) and Measurement & Verification (M&V) processes.
A payback period of 6.3 years has been estimated, and 190-200 tons of annual CO2 emissions will be avoided. The project has been implemented by ENGIE and financed by GOURMET, who also applied for an environmental subsidy from the Austrian Ministry for Sustainability and Tourism.
Apart from the actual energy savings in terms of calculated natural gas and electricity savings, the application of the ICP framework provides additional benefits to project owner GOURMET. Based on feedback from project developer Denkstatt & Enertec, compared to the standard approach of developing such projects additional focus is put on:
- The normalisation of the energy baseline (correlation and regression analyses),
- The development of the implementation plans, in particular
- Tasks and responsibilities,
- Training documents and manuals
- Systematic monitoring and correction measures.
According to Denkstatt & Enertec’s, the project owner particularly benefits from:
- More robust savings calculations and a more robust baseline for the verification of energy savings,
- An additional layer of quality assurance, and
- A stronger focus on proper project implementation (in addition to regular project development scope).
Furthermore, according to the project developer, ICP provides a clear and comprehensive standard which defines all required steps and documentation. Thus, this ensures that the project developer has a complete picture of the project, looks at everything very closely and probably thinks more about the regression analyses: which factors could affect energy consumption and what is their effect? Moreover, the review through an external and independent third-party quality assurance assessor, particularly the critical questions during this review process, ensures highest quality of the project development process.
Text: Creara (Madrid) Content provider: Investor Confidence Project