Ground-Coupled Heating-Cooling Systems in Urban Areas: How Sustainable Are They?

Abstract

Ground-coupled heating-cooling systems (GCHCSs) exchange heat between the built environment and the subsurface using pipework buried in trenches or boreholes. If heat pumps in GCHCSs are powered by “green electricity,” they offer genuine carbon-free heating-cooling; for this reason, there has been a surge in the technology in recent years. Interference between adjoining installations is being reported, raising issues of sustainability in terms of performance, equitable sharing of natural resources, and localized ecological impacts. Using an analytical model for heat transport in porous media, sensitivity analyses have been obtained for open-loop systems in typical hydro-geological settings for urban GSHCSs in the United Kingdom, revealing that breakthrough of injected water will likely lead to significant declines in system performance in less than 25 years for well spacings less than 300 m, unless injection rates are kept below 250 m³/d. Only by cooperatively planning will adjoining landowners in urban areas achieve large-scale sustainable system designs.

Keywords

carbon cooling energy groundwater heating heat pump soil sustainability

Get full access to this article

View all access options for this article.

References

Acornley, R.M. (1999). Water temperature within spawning beds in two chalk streams and implications for salmonid egg development. Hydrological Processes, 13, 439-446.

Ampofo, F. , Maidment, G.G. , & Missenden, J.F. (2006). Review of groundwater cooling systems in London. Applied Thermal Engineering, 26, 2055-2062.

Banks, D. (2007). An introduction to thermogeology: Ground source heating and cooling. Oxford, UK: Blackwell.

Chiasson, A.C. , Rees, S.J. , & Spitler, J.D. (2000). A preliminary assessment of the effects of ground-water flow on closed-loop ground-source heat pump systems. American Society of Heating, Refrigerating and Air-Conditioning Engineers Transactions , 106, 380-393.

Clauser, C. (2003). Numerical simulation of reactive flow in hot aquifers . Berlin: Springer-Verlag.

Clyde, C.G. , Govindachari, V. , & Madabhushi, M. (1983). Spacing of wells for heat pumps. Journal of Water Resources Planning and Management ( ASCE), 109, 203-212.

Ferguson, G. , & Woodbury, A.D. (2006). Observed thermal pollution and post-development simulations of low-temperature geothermal systems in Winnipeg, Canada. Hydrogeology Journal, 14, 1206-1215.

Jenkins, S. , & Hardwick, P. (2004). Groundwater protection and the UK drilling industry . Ground Engineering, 36(2), 26.

Manning, D.A.C. , Younger, P.L. , Smith, F.W. , Jones, J.M. , Dufton, D.J. , & Diskin, S. (2007). A deep geothermal exploration well at Eastgate, Weardale, UK: A novel exploration concept for low-enthalpy resources. Journal of the Geological Society, London, 164, 371-382.

10.

Sachs, H.M. (2002). Geology and drilling methods for ground-source heat pump installations: An introduction for engineers. Atlanta, GA: American Society of Heating, Refrigerating and Air-Conditioning Engineers.

11.

Sanner, B. , Karytsas, C. , Mendrinos, D. , & Rybach, L. (2003). Current status of ground source heat pumps and underground thermal energy storage in Europe. Geothermics , 32, 579-588.

12.

Shared Intelligence. (2006). Geothermal Research, Education and Training Institute—Development prospectus (Prepared for Easington District Council and Newcastle University). York, UK: Author.

13.

World Commission on Environment and Development. (1987). Our common future (The Brundtland Report). New York: Oxford University Press.

14.

Younger, P.L. (2006, September). Potential pitfalls for water resources of unregulated development of ground-source heat resources. Presented at the annual conference of the Chartered Institution of Water & Environmental Management, Newcastle upon Tyne, UK.

15.

Younger, P.L. (2007). Groundwater in the environment: An introduction . Oxford, UK: Blackwell.

16.

Younger, P.L. , & Adams, R. (1999). Predicting mine water rebound (Environment Agency R&D Technical Report W179). Bristol, UK: Environment Agency.