Coefficient of Performance

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maverick_friend Active Contributor Join Date: May 2015 Posts: 11	Coefficient of Performance 10/01/2018 10:45 AM
	Respected all, Request you to kindly help in giving explanation to the below statement: "When a building is heated it is suggested that 3 kWh of heat, 1.5 kWh of fuel and 1kWh of electricity have the same value." How could this be possible? Thanks in advance, Regards
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#5 "Re: Coefficient of Performance" by Rixter on 10/04/2018 12:51 PM (score 1)
#3 "Re: COP " by PWSlack on 10/01/2018 2:42 PM (score 1)
#2 "Re: COP " by SolarEagle on 10/01/2018 11:53 AM (score 1)

BruceFlorida Guru Join Date: Jul 2008 Posts: 1688 Good Answers: 145	#1 Re: COP 10/01/2018 10:53 AM
	Sounds like either an energy efficiency or economics question. Do either make sense for your source of the quote? __________________ Few things limit our potential as much as knowing answers and setting aside questions.
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SolarEagle Guru Join Date: Mar 2007 Location: by the beach in Florida Posts: 33392 Good Answers: 1817	#2 Re: COP 10/01/2018 11:53 AM
	"The coefficient of performance or COP of a heat pump, refrigerator or air conditioning system is a ratio of useful heating or cooling provided to work required.".. So it's a calculation of efficiency of your system in providing or removing, useful heat, that's the heat flowing from the system into your living space, or heat existing in your living space, not including, in the case of gas or oil burners, heat that is exhausted from the stack...so the efficiency of your system moving heat 'in to' or 'out of', your living space... So electric heat is nearly 100% efficient...the others are not because of waste heat...but the cost per btu of different fuels varies... https://en.wikipedia.org/wiki/Coefficient_of_performance __________________ All living things seek to control their own destiny....this is the purpose of life
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SolarEagle Guru Join Date: Mar 2007 Location: by the beach in Florida Posts: 33392 Good Answers: 1817	#4 In reply to #2 Re: COP 10/01/2018 3:39 PM
	"Kilowatthour generated per unit of fuel used = Fuel heat content (in Btu per physical unit) divided by Heat rate (in Btu per kWh)".... "To express the efficiency of a generator or power plant as a percentage, divide the equivalent Btu content of a kWh of electricity (3,412 Btu) by the heat rate. For example, if the heat rate is 10,500 Btu, the efficiency is 33%. If the heat rate is 7,500 Btu, the efficiency is 45%."... https://www.eia.gov/tools/faqs/faq.php?id=667&t=6 https://www.eia.gov/tools/faqs/faq.php?id=107&t=3 __________________ All living things seek to control their own destiny....this is the purpose of life
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PWSlack Guru Join Date: Jan 2007 Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on. Posts: 32175 Good Answers: 839	#3 Re: COP 10/01/2018 2:42 PM
	...which means that the COP on <...fuel...> is 2 and the COP on <...electricity...> is 3. __________________ "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
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Rixter Guru Join Date: Apr 2010 Location: About 4000 miles from the center of the earth (+/-100 mi) Posts: 9910 Good Answers: 1141	#5 Re: Coefficient of Performance 10/04/2018 12:51 PM
	The short answer is you can use electricity to run a heat pump. The total output of heat (to heat the building) is the energy (work) supplied by the electricity plus the amount of heat pumped from outside. This total is greater than the electricity supplied. If the energy (work) for the heat pump is supplied by combusting fuel, there is a loss of efficiency compared with electricity. http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/heatpump.html
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Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, vote them!

#5 "Re: Coefficient of Performance" by Rixter on 10/04/2018 12:51 PM (score 1)
#3 "Re: COP " by PWSlack on 10/01/2018 2:42 PM (score 1)
#2 "Re: COP " by SolarEagle on 10/01/2018 11:53 AM (score 1)

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