The perpendo Energie- und Verfahrenstechnik GmbH took 3rd place in the German Refrigeration Award 2011 in the category "climate-friendly air conditioning of a commercial building". The project "Operation optimisation of an administration site to reduce energy consumption and a sustainable improvement in energy quality" was awarded the price.

This project includes an operational optimisation of the existing situation with the clearly formulated target to reduce the greenhouse gas emissions of the site. The investigated site is a management site with a total of 11 buildings. The energy sources used are electricity, natural gas and fuel oil, where a total of five cooling plants produce cold water for air-conditioning. The air-conditioning systems, the data center, the static heating systems, and lighting are among the major energy aspects.

To make a sustainable contribution to the reduction of greenhouse gas emissions, a detailed analysis of the energy demand was carried out for the described property. The entire site was investigated by means of a complex simulation model in order to obtain a high degree of transparency. In addition to the detailed breakdown of the energy demand structure this approach ensures that individual improvement measures can be quantified taking into account interactions between measures under consideration.

In the present situation, the buildings were modeled in a dynamic building and plant simulation and simulated in hourly increments for an entire year. All relevant boundary conditions, such as weather, the geometry of the building, the building physics and all technical building equipment is taken into account. During the investigation special attention was given to the area of ventilation, because the demand in this area can usually be influenced easily and also makes up a substantial share of the total energy requirement of the site. The simulation model was validated using metered data, so that a consistent picture of the energy flow was obtained. Following this sensitivity analyses were conducted to identify and evaluate the unused energy savings potentials.

The analysis identified primarily measures which were to be found in the adaptation of the controls of the air conditioning systems through a demand-oriented control strategy. Significant savings in the areas of cooling, electricity and natural gas usage could be achieved through the implementation of the measures. To this end mainly low investment improvements were carried out, which were limited largely to reprogramming the controls of the ventilation systems. In addition some refurbishments (e. g. heat recovery systems) have been made. In addition to the quantification of efficiency measures, the simulation model provides a dynamic profile of the cooling load (in hourly increments over the entire the year), so that it is possible to re-evaluate the cooling supply of the site. Taking the reduced consumption into account, combining different cooling plants is currently being considered. In this context an efficiency evaluation of the existing chillers is also being conducted.

The project shows that there is significant potential for the reduction of greenhouse gas emissions in the building stock. This example makes clear how important it is to have sufficient knowledge of the energy situation in order to conduct a targeted optimisation of existing plants. It has been shown that a detailed investigation by means of model-based analyses using suitable simulation tools is an effective means of obtaining the necessary energy knowledge. The high transparency of the existing energy flows of the site resulted in a series of improvement measures. In this case the carbon dioxide emissions for the entire site could be lowered sustainably by 27 %. Since the measures largely required only low investments, this reduction could be realised with a payback period of the overall package of about a year. The good results of the analysis could be confirmed by subsequent energy controlling. The selected approach has generated significant added value for the customer, not only monetarily, but also in terms of a time benefit in implementing own reduction targets.

German Refrigeration Award 2011, Benchmark

Further information on the German Refrigeration Award can be obtained here. >


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