THESIS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY Efficiency of building related pump and fan operation Application and system solutions CAROLINE MARKUSSON Building Services Engineering Department of Energy and Environment CHALMERS UNIVERSITY OF TECHNOLOGY Göteborg, Sweden 2011 i EFFICIENCY OF BUILDING RELATED PUMP AND FAN OPERATION Application and system solutions Caroline Markusson © CAROLINE MARKUSSON, 2011 ISBN 978-91-7385-588-4 Doktorsavhandling vid Chalmers tekniska högskola Ny serie nr 3269 ISSN 0346-718X Technical report D2011:02 Building Services Engineering Department of Energy and Environment Chalmers University of Technology SE-412 96 GÖTEBORG Sweden Telephone +46 (0)31 772 1000 Printed by Chalmers Reproservice Göteborg 2011 ii Efficiency of building related pump and fan operation Application and system solutions CAROLINE MARKUSSON Building Services Engineering Chalmers University of Technology Abstract The electric energy use in Swedish non-industrial buildings is 71 TWh per year out of which 30 TWh per year is used for the operation of technical systems. A significant part of those 30 TWh/year is used for pump and fan operation. The Swedish parliament decided in 2009 on a national energy and climate plan. By the year 2050 the energy use per unit conditioned floor area in the Swedish building stock must be halved compared to the year of 1995. The objective of this thesis is to find means to reduce pump and fan energy in the non-industrial buildings. The aim is to find systems and components that can provide energy reduction in pump and fan systems by 50 %. In the thesis the current situation in non-industrial buildings regarding pump and fan systems has been described and the energy saving potentials, both at component and at system level, have been identified and discussed. Furthermore, the possibility of decentralized pump and fan systems has been examined. The calculated saving potential is 50 % and 40 % respectively for pump and fan operation in non-industrial buildings. This may be achieved by improving pump efficiency and specific fan power to state-of-the-art efficiency and recommended SFP values. System changes can also provide major additional energy savings in pump and fan operation. A decentralized pump heating system has been implemented in real life and results show a reduction of pump energy by 70 %. The theoretical parts of the thesis are supported by four case studies in real buildings and by three laboratory studies. Keywords: air systems, control-on-demand, decentralized systems, efficiency, electric energy, electric motor, fan, hydronic systems, local systems, motor drive, pump, variable speed, iii This thesis has been funded by the Swedish Energy Agency/CERBOF (project no. 430547-1), Formas-Bic (project no. 244-2008-99) and Göteborg Energi foundation for Research and Development (project no. 10-2008-0165/13) within the project Energy efficient pump and fan operation in buildings to Building Services Engineering of Chalmers University of Technology. iv Acknowledgment The financial support given by Göteborg energy, Energimyndigheten and Formas Bic is gratefully acknowledged. In addition I would like to thank all the companies that have been involved in the project for their times spent and valuable discussions. Special thanks to Honeywell, Wilo, Grundfos, LGG Inneklimat, LogiCO2, Swegon, Akademiska hus and Västfastigheter for helping me with test objects and equipment. I would like to thank my supervisor Ass. Professor Lennart Jagemar for his guidance, encouragement and shared knowledge. I would like to thank Professor Per Fahlén for giving me this opportunity and for sharing his knowledge and visions. I would also like to thank all my colleagues at Building services engineering. Especially thanks to Håkan Larsson for his invaluable help and patience in the laboratory and Tommy Sundström for all his help and support with measurements and computers. Finally, I would like to thank Prof. Torbjörn Thiringer and Dr. Johan Åström at the Division of Electric Power Engineering for good cooperation. My love is reserved for my family who has always been there for me. Companies involved in the project: Akademiska hus LogiCO2 Astra Zeneca Mare Trade Cadcom MedicHus Göteborgs Stads Bostads Nibe Danfoss Swegon Fläkt Woods Systemair Gothia Power Schneider Electric Grundfos Thermia Värme Göteborg Energi Tour and Andersson Honeywell Västfastigheter IVT Wilo LGG Inneklimat Åf –Installation Göteborg October 2011 Caroline Markusson v vi Contents Page Abstract iii Acknowledgment v Symbols x  Latin letters x  Greek letters x  Subscripts xi  Abbreviations xii  Dimensionless numbers xii  1  Introduction 1  1.1  Background 1  1.2  Objective 1  1.3  Methodology 1  1.4  Outline of the thesis 2  1.5  List of publications 2  2  Literature review 5  2.1  Pumps and liquid systems 5  2.2  Fans and air systems 9  2.3  Electric motors and motor drives 13  2.4  Literature review summary 15  3  Building related electric energy to pumps and fans in Sweden 17  3.1  Energy use and conditioned floor area for non-industrial buildings 17  3.2  Pump operation – power, time of operation and energy use 20  3.3  Fan operation – power, time of operation and energy use 27  3.4  Pump and fan energy use - summary 33  4  Current HVAC system design - Pump and fan duty 35  4.1  Design criteria 35  4.2  Liquid systems 37  4.3  Air systems 39  4.4  Current use and future possibilities 41  5  Future HVAC system design - Pump and fan duty 43  5.1  Design criteria 43  5.2  Liquid systems 44  5.3  Air systems 46  5.4  Requirements on future components and control systems 49  5.5  Discussion 61  6  System simulation example 63  6.1  Model and model validation 63  6.2  Simulation for case study II 70  7  Case studies and laboratory tests 77  7.1  Case study I: Conventional use of central VSD pumps 77  7.2  Case study II: Future design with local VSD pumps/ centralized to decentralized pump system design 84  7.3  Case study III: Heat exchangers - run around loop and enthalpy wheel 92  7.4  Case study IV: Air heaters and air coolers 103  7.5  Laboratory test I: Pump efficiency 108  vii 7.6  Laboratory test II: Control of heating-coil capacity by local VSD pump 114  7.7  Laboratory test III: Control of cooling-coil capacity by local VSD pump 116  8  Discussion, conclusions and future work 123  8.1  Discussion 123  8.2  Conclusion 125  8.3  Future work 127  References 129  Appendix A 137  Flow measurements 137  Budget of uncertainty for the flow measurement 139  Differential pressure measurements 139  Power measurements 140  Uncertainty budget for the pump efficiency measurement 140  viii ix Symbols Latin letters C heat capacity flow rate (C  M c ) [W/K] p c specific heat capacity at constant pressure (fluids) [J/(kg·K)] p D diameter [m] n rotational speed [revs/s] p pressure (pressure difference is designated p, see ) [Pa] Q thermal capacity [W] SFP Specific Fan Power [kW/(m3/s)] SPP Specific Pump Power [kW/(m3/s)] T torque [Nm] t celsius temperature [°C] U thermal transmittance (total coefficient of heat transfer) [W/(m2K)] V volume [m3] V volume flow rate [m3/s] W power (mechanical or electric) [W] W technical power (mechanical or electric) [W] t K radiator constant [W/Kn] n radiator exponent [-] Greek letters  valve authority [-] p pressure difference [Pa or kPa] (cid:2016) logarithmic mean temperature difference [K or °C] lm (cid:2016) arithmetic mean temperature difference [K or °C] am ε effectiveness [-]  efficiency [-]  temperature efficiency [-] t  density [kg/m3]  time [s]  angular velocity [radians/s] x