geothermal direct heat utilization. district heating

GEOTHERMAL DIRECT HEAT UTILIZATION

DISTRICT HEATING

GREENHOUSE HEATING

SWIMMING, BATHING BALNEOLOGY

FISH FARMING

http://www.geothermal.marin.org/GEOpresentation/sld023.htm

GROUND SOURCE HEAT PUMP



(a) Categories of Capacity % for 2005 and (b) (b) energy use in %, 2005

(Lund, Freeston and Boyd, 2005).

Summary of Worldwide Direct-Use Categories (Lund, Freeston and Boyd, 2005).

DISTRICT HEATING

Distribution of hydrothermal water from one or more wells to several houses, buildings and blocks


• It is the largest sector of geothermal energy direct use in the world.

• It involves the distribution of heat (hot water or steam) from a central location, through a network of pipes to individual houses or blocks of buildings.

• Geothermal Heating Systems are in operation in at least 12 countries.

DISTRICT HEATING

DISTRICT HEATINGEXAMPLE-1

Degree-days = Number of days (Design room temperature-Daily mean temperature)

loadheatPeak

yeartheoverloadheatAveragefactorLoad

100demandMaximum

daygivenaatDemand(%)Load

Heat Pump Technology

• The Earth as a heat source and sink

• Heating in winter and cooling in summer

• In the USA and Europe


GHPs use the stable temperature of the ground;

• as a heat source to warm buildings in winter

• as a heat sink to cool buildings in summer

• also for water heating by desuperheaters


The system includes three principal components:

• Geothermal earth connection subsystem • Geothermal heat pump subsystem • Geothermal heat distribution subsystem


Earth Connection Subsystem

• buried in the ground near the building • either vertical or horizontal• circulates a fluid (water, or a mixture of water and antifreeze)


A heat pump is a device which uses heat on a low temperature level, and transfer the heat to a higher, useful

temperature level using an external driving force (mechanical energy or high-temperature heat)


A heat pump is a device which uses heat on a low temperature level, and transfer the heat to a higher, useful

temperature level using an external driving force (mechanical energy or high-temperature heat)

Heat flows naturally from a higher to a lower temperature. Heat pumps, however, are able to force the heat flow in the

other direction, using a relatively small amount of high quality drive energy (electricity, fuel, or high-temperature waste

heat). Thus heat pumps can transfer heat from natural heat sources in the surroundings, such as the air, ground or water,

or from man-made heat sources such as industrial or domestic waste, to a building or an industrial application.



In order to transport heat from a heat source to a heat sink, external energy is needed to drive the heat pump.

Because heat pumps consume less primary energy than conventional heating systems, they are an

important technology for reducing gas emissions that harm the environment, such as carbon dioxide (CO2),

sulphur dioxide (SO2) and nitrogen oxides (NOx).


Almost all heat pumps currently in operation are either based

on a vapor compression, or on an absorption cycle.

GROUND SOURCE HEAT PUMPVAPOR COMPRESSION

geothermal direct heat utilization. district heating

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