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Ellerbrok C.,Fraunhofer Institute for Building Physics
Energy Procedia | Year: 2014

Within this work, load-shifting possibilities of heat pumps in residential buildings as well as its influencing and limiting factors are displayed. The intermediate storage is achieved by using the thermal mass of the building so the heat supply can be postponed from the heat demand for a certain period, depending on the characteristics of the building. No additional water storage is considered. © 2014 The Authors.

Bujedo L.A.,CARTIF Centro Tecnologico | Rodriguez J.,Fraunhofer Institute for Building Physics | Martinez P.J.,University Miguel Hernandez
Solar Energy | Year: 2011

In this article, different control strategies used in a solar cooling installation are presented and compared, publishing real working data from three summer periods, with the system working at part load.The facility consists of two solar fields that feed a heating system during the winter and a 35. kW Li-Br absorption chiller during the summer period to cool part of an office building.The improvements obtained using control based on critical radiation and a variable flow mass have been compared on the solar plant with a conventional constant flow control. In the same way, the improvements obtained in the yields of a cooling production plant have been compared when programming three different controls: the first one with fixed flow masses, the second adapting the temperature on the condenser as a function of the generator temperature (constant flow mass), and the third adapting the condenser temperature and the flow mass on the generator as a function of the system loads. © 2011 Elsevier Ltd.

Lohani S.P.,University of Oldenburg | Schmidt D.,Fraunhofer Institute for Building Physics
Renewable Energy | Year: 2010

The energy and exergy flow for a space heating systems of a typical residential building of natural ventilation system with different heat generation plants have been modeled and compared. The aim of this comparison is to demonstrate which system leads to an efficient conversion and supply of energy/exergy within a building system. The analysis of a fossil plant heating system has been done with a typical building simulation software IDA-ICE. A zone model of a building with natural ventilation is considered and heat is being supplied by condensing boiler. The same zone model is applied for other cases of building heating systems where power generation plants are considered as ground and air source heat pumps at different operating conditions. Since there is no inbuilt simulation model for heat pumps in IDA-ICE, different COP curves of the earlier studies of heat pumps are taken into account for the evaluation of the heat pump input and output energy. The outcome of the energy and exergy flow analysis revealed that the ground source heat pump heating system is better than air source heat pump or conventional heating system. The realistic and efficient system in this study "ground source heat pump with condenser inlet temperature 30 °C and varying evaporator inlet temperature" has roughly 25% less demand of absolute primary energy and exergy whereas about 50% high overall primary coefficient of performance and overall primary exergy efficiency than base case (conventional system). The consequence of low absolute energy and exergy demands and high efficiencies lead to a sustainable building heating system. © 2009 Elsevier Ltd. All rights reserved.

Schmidt D.,Fraunhofer Institute for Building Physics
International Journal of Exergy | Year: 2012

An optimisation of the exergy fl ows in buildings and the supply structures related to them, similar to other thermodynamic systems, can help in identifying the potential of increased effi ciency in energy utilisation. The low exergy (LowEx) approach entails matching the quality levels of exergy supply and demand to streamline the utilisation of high-value energy resources. This approach is the key concept for the conducted work. Using a typical case, the advantages of the analyses and the difference between energy and exergy analyses are demonstrated. In conclusion, suggestions, based on an analysis of a real and existing building, are presented for a benchmarking system for so-called LowEx buildings. Copyright © 2012 Inderscience Enterprises Ltd.

Ilg R.,Fraunhofer Institute for Building Physics
Green Design, Materials and Manufacturing Processes - Proceedings of the 2nd International Conference on Sustainable Intelligent Manufacturing, SIM 2013 | Year: 2013

With the growing environmental awareness in society, the demand for sustainable products and services increases. Hence especially in the expanding aviation sector, a reduction of the ecological impacts is intended to improve the aviation's ecological footprint. Modelling a whole life cycle inventory in a LCA study compliant with the ISO 14040 requires comprehensive expert knowledge. Furthermore aircrafts are complex systems with millions of different parts and various, aviation specific materials. To enable non-experts with little or no LCA knowledge like aircraft designers to assess the environmental impacts of already existing and also of conceptual aircrafts by the method of LCA, the web-based Tool EcoSky was developed with an easy-to-use user interface. In this Tool, the complex LCI modelling is decoupled from the design process. The presentation highlights the characteristics of the aerospace sector and how the EcoSky Tool deals with the specific difficulties. © 2013 Taylor & Francis Group.

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