Simulation of a solar assisted combined heat pump – Organic rankine cycle system

Abstract A novel solar thermal and ground source heat pump system that harnesses the excess heat of the collectors during summer by an Organic Rankine Cycle (ORC) is simulated. For the ORC the heat pump process is reversed. In this case the scroll compressor of the heat pump runs as a scroll expander and the working fluid is condensed in the ground heat exchanger. Compared to a conventional solar thermal system the only additional investments for the combined system are a pump, valves and upgraded controls. The goal of the study is to simulate and optimize such a system. A brief overview of the applied models and the evolutionary algorithm for the optimization is given. A system with 12 m 2 of flat plate collectors installed in a single family house is simulated for the locations Ankara, Denver and Bochum. The ORC benefits add up to 20–140 kW h/a, which reduces the net electricity demand of the system by 1–9%. Overall 180–520 € are saved over a period of 20 years, which can be enough to cover the additional investments.

[1]  Lucien Wald,et al.  The European Solar Radiation Atlas: a valuable digital tool , 2001 .

[2]  J. Claesson,et al.  New Analytical and Numerical Solutions for the Short-term Analysis of Vertical Ground Heat Exchangers , 2011 .

[3]  Mauro Venturini,et al.  Experimental Implementation of a Micro-Scale ORC-Based CHP Energy System for Domestic Applications , 2010 .

[4]  Saffa Riffat,et al.  Solar-powered Rankine system for domestic applications , 1996 .

[5]  Jeffrey D. Spitler,et al.  A short time step response factor model for vertical ground loop heat exchangers , 1999 .

[6]  Jean Lebrun,et al.  Experimental analysis and simplified modelling of a hermetic scroll refrigeration compressor , 2002 .

[7]  W. Beckman,et al.  Solar Engineering of Thermal Processes , 1985 .

[8]  Per Lundqvist,et al.  Dynamic simulation of a solar-driven carbon dioxide transcritical power system for small scale combined heat and power production , 2010 .

[9]  Louis Lamarche,et al.  A fast algorithm for the hourly simulations of ground-source heat pumps using arbitrary response factors , 2009 .

[10]  Per Eskilson.  Thermal analysis of heat extraction boreholes , 1987 .

[11]  Hiroshi Yamaguchi,et al.  Theoretical analysis of a thermodynamic cycle for power and heat production using supercritical carbon dioxide , 2007 .

[12]  Roland Span,et al.  Techno-economic evaluation of a solar assisted combined heat pump – Organic Rankine Cycle system , 2015 .

[13]  Louis Lamarche,et al.  A fast algorithm for the simulation of GCHP systems , 2007 .

[15]  Kenya Standard,et al.  Thermal solar systems and components — Solar collectors — Part 2: Test methods , 2008 .

[16]  H. Baehr,et al.  An International Standard Formulation for the Thermodynamic Properties of 1,1,1,2‐Tetrafluoroethane (HFC‐134a) for Temperatures from 170 K to 455 K and Pressures up to 70 MPa , 1994 .

[17]  P. Ineichen,et al.  A new simplified version of the perez diffuse irradiance model for tilted surfaces , 1987 .

[18]  Noboru Yamada,et al.  Solar Rankine Cycle System Using Scroll Expander , 2007 .

[19]  R. Peterson,et al.  Performance of a small-scale regenerative Rankine power cycle employing a scroll expander , 2008 .

[20]  Peter A. Jacobs,et al.  Dynamic performance estimation of small-scale solar cogeneration with an organic Rankine cycle using a scroll expander , 2013 .

[21]  Vincent Lemort,et al.  Design, modeling and experimentation of a reversible HP/ORC prototype , 2014 .

[22]  M. McLinden,et al.  NIST Standard Reference Database 23 - NIST Thermodynamic and Transport Properties REFPROP, Version 7.0 , 2002 .

[23]  Sebastian Herkel,et al.  A statistical analysis on market-available solar thermal heat pump systems , 2013 .

[24]  Vincent Lemort,et al.  Pure and Pseudo-pure Fluid Thermophysical Property Evaluation and the Open-Source Thermophysical Property Library CoolProp , 2014, Industrial & engineering chemistry research.

[25]  Hiroshi Yamaguchi,et al.  Solar energy powered Rankine cycle using supercritical CO2 , 2006 .

[26]  Hailei Wang,et al.  Experimental performance of a compliant scroll expander for an organic Rankine cycle , 2009 .

[27]  Vincent Lemort,et al.  Testing and modeling a scroll expander integrated into an Organic Rankine Cycle , 2009 .

[28]  Jiang Wang,et al.  Performance evaluation of a low-temperature solar Rankine cycle system utilizing R245fa , 2010 .

[29]  Lourdes García-Rodríguez,et al.  Analysis and optimization of the low-temperature solar organic Rankine cycle (ORC) , 2010 .

[30]  Daniel Favrat,et al.  Experimental Investigation of a Hermetic Scroll Expander–Generator. , 1994 .