District cooling 1

District coolingDistrict cooling is the opposite of district heating. Working on broadly similar principles to district heating, districtcooling delivers chilled water to buildings like offices and factories needing cooling. In winter, the source for thecooling can often be sea water, so it is a cheaper resource than using electricity to run compressors for cooling.The Helsinki district cooling system uses otherwise wasted heat from summer time CHP power generation units torun absorption refrigerators for cooling during summer time, greatly reducing electricity usage. In winter time,cooling is achieved more directly using sea water. The adoption of district cooling is estimated to reduce theconsumption of electricity for cooling purposes by as much as 90 per cent and an exponential growth in usage isforecast.[1] The idea is now being adopted in other Finnish cities. The use of district cooling grow also rapidly inSweden in a similar way.[2]

Cornell University's Lake Source Cooling System uses Cayuga Lake as a heat sink to operate the central chilledwater system for its campus and to also provide cooling to the Ithaca City School District. The system has operatedsince the summer of 2000 and was built at a cost of $5560 million. It cools a 14,500 tons (50 MW) load.In August 2004, Enwave Energy Corporation, a district energy company based in Toronto, Canada, started operatinga system that uses water from Lake Ontario to cool downtown buildings, including office towers, the Metro TorontoConvention Centre, a small brewery and a telecommunications centre. The process has become known as Deep LakeWater Cooling (DLWC). It will provide for over 40,000 tons (140 MW) of coolinga significantly larger systemthan has been installed elsewhere. Another feature of the Enwave system is that it is integrated with Torontosdrinking water supply. The Toronto drinking water supply required a new intake location that would be further fromshore and deeper in the lake. This posed two problems for the utility that managed the city's drinking water supply:1. the capital cost of moving the water intake location and additionally, the new location would supply water thatwas so cold it would require heating before it could be distributed. The cooperation of the district cooling agency,Enwave, solved both problems: Enwave paid for the cost of moving the water intake and also supplied the heat towarm the drinking water supply to acceptable levels by effectively extracting the heat from the buildings it served.Contact between drinking water and the Enwave cooling system is restricted to thermal contact in a heat exchanger.Drinking water does not circulate through the Enwave cooling systems. [citation needed]

In January 2006, PAL technology is one of the emerging project management companies in UAE involved in thediversified business of desalination, sewage treatment and district cooling system. More than 400,000 Tons (1400MW) of district cooling projects are planned. The Palm Jumeirah utilises district cooling supplied by Palm UtilitiesLLC [3] to provide air conditioning for buildings on the trunk and crescent of the Palm.In 2006, a district cooling system came online in Amsterdam's Zuidas, drawing water from the Nieuwe Meer[4][5]

On the 9th of November 2010, The world's largest district cooling plant opened at The Pearl-Qatar. This plant isowned and operated by Qatar District Cooling Company (known as Qatar Cool [6]). It is capable of cooling a load of130,000 tons (450 MW). [7]

If the other renewable alternatives are too warm during the summer or too expensive, cold storage can beinvestigated. In large scale applications underground and snow storage are the most likely alternatives. In anunderground storage the winter cold is heat exchanged from the air and loaded into the bedrock or an aquifer by oneor more bore holes. In a snow storage frozen water (snow and/or ice) is saved in some kind of storage (pile, pit,cavern etc.). The cold is utilized by pumping melt water to the cooling object, directly in a district cooling system orindirect by a heat exchanger. The lukewarm melt water is then pumped back to the snow where it gets cooled andmixed with new melt water. Snow cooling works as a single cold source but can also be used for peak cooling sincethere is no relevant cooling limit.[8] In Sweden there is one snow cooling plant in Sundsvall, built and owned by thecounty. The cooling load in Sundsvall is about 2000 kW (570 tons of refrigeration) and 1500 MWh/year.[9]

District cooling 2

Especially in subtropical regions not only cooling, but dehumidifying of the air becomes important. Liquid desiccantcooling allows to generate remotely and efficiently a moisture absorbing liquid. This liquid can be pumped ortransported long distances without energy loss. [10]

References[1] (http:/ / www. helsinginenergia. fi/ en/ cool/ os3_3a. html)[3] http:/ / www. palmutilities. ae[4] Lake water air conditioning cuts CO2 emissions by 70% compared to conventional cooling (http:/ / www. nycclimatesummit. com/

casestudies/ water/ water_amsterdam. html)[6] http:/ / www. qatarcool. com[8] http:/ / epubl. ltu. se/ 1402-1544/ 2005/ 30/ LTU-DT-0530-SE. pdf

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Article Sources and ContributorsDistrict cooling Source: http://en.wikipedia.org/w/index.php?oldid=562797012 Contributors: A333, Coastwise, Gralo, HartzR, Mindmatrix, Ojdo, Tonysole, Vegaswikian, 1 anonymous edits

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