Abstract
During the past decade, increasing local and global problems regarding energy, the environment, and the economy have created one of the biggest challenges for human beings to combat through sustainable solutions. District energy systems (DESs) for distributed heating and/or cooling, known also as district heating and cooling (DHC) systems, appear to be part of the solutions. In some situations, for example in the case of a major power plant, it may appear economically attractive to build a pipe network that distributes the ejected heat among a number of residential/commercial/industrial users covering a territory around the central power plant. Cogeneration, geothermal, or solar energy systems are the most suitable for being coupled to DHC. Steam, hot or cold water, or ice slurry can be used as heat-conveying fluids. The opportunity of using a DES must be judged first on an economic basis by comparison of the life-cycle cost (LCC) with the cost of other competing systems, such as electrically driven heat pumps at the user’s location.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Abbreviations
- \( \dot{E}x \) :
-
Exergy rate, W
- f :
-
Figure of merit
- h :
-
Specific enthalpy, kJ/kg
- \( \dot{m} \) :
-
Mass flow rate, kg/s
- \( \dot{Q} \) :
-
Heat rate, W
- s :
-
Specific entropy, kJ/kg K
- T :
-
Temperature, K
- \( \dot{W} \) :
-
Work rate, W
- η :
-
Energy efficiency
- ψ :
-
Exergy efficiency
- 0:
-
Reference state
- c:
-
Cooling
- c,u:
-
Useful cooling
- DC:
-
District cooling
- DH:
-
District heating
- DHC:
-
District heating and cooling
- e:
-
Electrical
- h:
-
Heating
- h,u:
-
Useful heat
- L:
-
Line
- S:
-
Source or system
- \( \overline {\left( {} \right)} \) :
-
Average value
- s:
-
Radiators and fan coils
- w:
-
Water heater
References
ASHRAE 1999. Handbook of Heating, Ventilating and Air Conditioning Applications, SI eds., American Society of HVAC&R, Atlanta, GA.
ASHRAE 2008. Handbook of Applications, SI eds., Chapter 11: Owning and operating costs. American Society of HVAC&R, Atlanta, GA.
Bel O., Hunyadi-Kiss I., Zweig S., Lallemand A. 1996. Thermal study of an ice slurry used as refrigerant in a cooling loop. International Institute of Refrigeration (IIR) Commissions B1, B2, E1, E2-Aarhus (Denmark).
Bloomquist R., Nimmons J. 2000. Geothermal district energy. In: Course on Heating with Geothermal Energy: Conventional and New Schemes, Lienau P.J. eds., WGC-2000 Short Courses, 8-10 June, Kazuno, Japan, pp. 85–136.
ConEd 2008. Consolidated Edison Company of New York. http://www.coned.com/ (accessed on November 6, 2008).
Dincer I. 2000. Renewable energy and sustainable development: a crucial review. Renewable and Sustainable Energy Reviews 4:157–175.
Dincer I. 2002. The role of exergy in energy policy making. Energy Policy 30:137–149.
Dincer I., Hepbasli A. 2010. District energy systems. In: Encyclopedia of Energy Engineering Technology, Capehart B.L. ed., Chapter 43. CRC Press, New York.
Dincer I., Rosen M.A. 2005. Thermodynamic aspects of renewables and sustainable development. Renewable and Sustainable Energy Reviews 9:169–189.
Edmonton Power 1991. City of Edmonton District Energy Development Phase. Section 2: Engineering Report.
Enwave 2005. History of District Energy. Internet source http://www.enwave.com/enwave/view.asp?/solutions/heating/history (accessed on November 6, 2008).
Hepbasli A, Canakci C. 2003. Geothermal district heating applications in Turkey: a case study of Izmir–Balcova. Energy Conversion and Management 44:1285–1301.
IEA 2004. Implementing agreement on district heating and cooling including the integration of CHP. Strategy Document. International Energy Agency, Paris.
JcMiras 2008. Estimated Capital Cost of Power Generating Plant Technologies. Internet source http://www.jcmiras.net/surge/p130.htm (accessed on November 7, 2008).
Karlsson T. 1982. Geothermal district heating the Iceland experience. UNU Geothermal training Programme. Iceland, Report 1982–4.
MacRae K.M. 1992. Realizing the Benefits of Community Integrated Energy Systems. Canadian Energy Research Institute, Calgary, Alberta.
National Academy of Sciences 1985. District Heating and Cooling in the United States: Prospects and Issues. Committee on District Heating and Cooling, National Research Council.
Ozgener L., Hepbasli A., Dincer I. 2004. Thermo-mechanical exergy analysis of Balcova geothermal district heating system in Izmir, Turkey. ASME Journal of Energy Resources Technology 126:293–301.
Rosen M.A., Le M.N., Dincer I. 2004. Thermodynamic assessment of an integrated system for cogeneration and district heating and cooling. International Journal of Exergy 1:94–110.
Rosen M.A., Le M.N., Dincer I. 2005. Efficiency analysis of a cogeneration and district energy system. Applied Thermal Engineering 25:147–159.
Skagestad B., Mildenstein P. 2002. District heating and cooling connection handbook. International Energy Agency.
Strickland C., Nyboer J. 2002. Cogeneration Potential in Canada–Phase II. Report for Natural Resources Canada.
UNEP 2005. Cogeneration, Energy Technology Fact Sheet, Division of Technology, Industry and Economics-Energy and Ozone Action Unit. Internet source http://www.uneptie.org/energy (accessed at November 6, 2008).
Author information
Authors and Affiliations
Corresponding author
Study Questions/Problems
Study Questions/Problems
-
10.1
Define district energy systems and explain their benefit.
-
10.2
List some technical characteristics of district energy systems.
-
10.3
Explain the benefit of cogeneration with respect to power-only generation.
-
10.4
Consider the general system from Fig. 10.3. Make reasonable assumptions regarding the efficiency of each unit and then determine the efficiency of the overall system.
-
10.5
Describe how district energy systems benefit the environment.
-
10.6
Describe the role of district energy systems in sustainable development.
-
10.7
A GDHS provides heat from the harvested thermal energy that is available at 80°C and a flow rate of 200 kg/s. At the central station, the heat exchanger that recirculates the water through the geothermal loop is placed while the reinjected water temperature is 50°C. The power consumption to run the pumps is 150 kW. The heat exchanger loses 1% of thermal energy through insulation. In the distribution network, hot water is circulated at a rate of 80 kg/s with the associated electricity consumption of 35 kW and has the maximum temperature of 70°C. The hot fluid reaches the user’s location with 65°C temperature and leaves it with 55°C. An amount of 7% of the delivered heat at the user’s location is lost due to imperfect insulation. Calculate the energy and exergy efficiency of the system and its components.
-
10.8
Define the life-cycle cost in the context of distributed energy systems.
-
10.9
List and explain the main cost components of a distributed energy system.
-
10.10
What represents the capital cost and how it can be estimated?
-
10.11
Define “depreciation” and explain its calculation.
-
10.12
Define the “cost of operating energy” and explain its calculation.
-
10.13
Estimate the life-cycle cost of the district energy system illustrated in Fig. 10.8 that used a CHP coal plant with a scrubber and a served a territory of 2 km2, for the following input data: peak electrical power P e = 200 MWe; load factor l = 75%; efficiency 25% (power cycle), 90% (mechanical to electrical); price of coal for the first year c coal = $3.0/GJ and r e = 10% price escalation rate; heat losses at power plant f = 5%; absorption chillers’ COP = 0.6; specific cost of cooling plant c c = $600/kW; cost of distribution line c L = $4,100/m; length of pipe network L = 10 km; fan coil unit cost c fc = $110/kW; number of years of service N = 30; inflation rate i = 1%, market discount rate r m = 6%, market loan rate r mL = 5%; other financial parameters f Loan = 0.8, t = 40%, t cred = 2%, f salv = 10%, t salv = 20%, f prop = 50%, t prop = 25%, f omi = 1%.
-
10.14
In order to assess the feasibility of the district energy system presented in Example 10.2, compare its life-cycle cost to a system that uses local heating and cooling through vapor compression heat pumps. Each heat pump unit has the capacity of 1 kW for both the cooling and the heating mode. The cost of a heat pump/air condition unit is $800/kW. To make the two systems equivalent, the number of heat pump units is the same as the number of fan coils, that is 30,500 units. In the local heat pump case, there is no need of a heat and cold distribution network, therefore the capital investment is lower; however, the electricity/fuel consumption is larger.
-
10.15
Using the cost analysis presented in the text, perform a parametric study to determine the optimum diameter of a pipe if the flow rate and the length are imposed.
-
10.16
Conduct a parametric study to determine the optimal thickness of the insulation of a buried pipe.
Rights and permissions
Copyright information
© 2011 Springer Science+Business Media, LLC
About this chapter
Cite this chapter
Dinçer, İ., Zamfirescu, C. (2011). District Energy Systems. In: Sustainable Energy Systems and Applications. Springer, Boston, MA. https://doi.org/10.1007/978-0-387-95861-3_10
Download citation
DOI: https://doi.org/10.1007/978-0-387-95861-3_10
Published:
Publisher Name: Springer, Boston, MA
Print ISBN: 978-0-387-95860-6
Online ISBN: 978-0-387-95861-3
eBook Packages: EngineeringEngineering (R0)