what's the enthalpy of feed water at 50 c_ - yahoo! answers

1/3/13 What's the enthalpy of f eed water at 50 C? - Yahoo! Answers

1/2answers.y ahoo.com/question/index?qid=20090227003212AAh70Ct

AdChoices

Home > All Categories > Science & Mathematics > Engineering > Resolved Question

Other Answers (1)

What's the enthalpy of feed water at 50 C?

I have a question which supplies the following information.The performance of an oil fired boiler, in producing steam at 10 bar absolute and 0.90 dryness fraction, showed thefollowing results: -Steam produced per hour = 2000kgFeed water temperature = 50COil used per hour = 160kgCalorific value of the fuel = 42.0MJ/kg

Use the appropriate steam table to calculate the thermal efficiency of the boiler under these conditions.

I have got the steam tables but haven't been told (and can't find) the changes the 50 C feed water will make to theoverall efficiency. Can someone tel me how to work out the enthalpy of the water at 50 C please?

4 years ago ( 2009-02-27 08:32:12 +0000 ) Report Abuse

zzwol

Best Answer - Chosen by Voters

E= m * Cp * Tusing Cp = 4.184 J/g-Deg C

T= TEMPERATURE difference (initial water temp & final water temp)

m= mass


100% 1 Vote

sabyashachi b

In using the steam tables to find the enthalpy, you only have one choice, that is to use the enthalpy of saturatedwater at 50C. From the steam tables, that value is:

209.32 kJ/kg

This may be listed as Hf or hf on the table heading. As feedwater, the actual pressure of the fluid may be abovesaturation, but for subcooled liquids like this, the enthalpy is more dependent on the temperature than the pressure.Since you were directed to the steam tables n the problem, I'd use the number above in your calculation.

Source(s):

power engineer


0% 0 Votes

oeman50

New User? Register Sign In Help Get new Yahoo! Mail apps Mail My Y! Yahoo!

Search Search Web

http://clicks.beap.bc.yahoo.com/yc/YnY9MS4wLjAmYnM9KDE1ajI1ZGszNihnaWQkTDZSekNXS0w2eEQ0NXRIeFVPR0ZIaEREZE1xMVRWRGx4Mk1BRFR4XyxzdCQxMzU3MjM2MDY3OTMzMjQwLHNpJDQ0MDY1NTEsc3AkMjExNDcwMDgwMCxjciQzMDg1NTIxMDUxLHYkMi4wLGFpZCQ2T2JDU0dLTDRNZy0sY3QkMjUseWJ4JFVSVzJFVy5ldWFnSU02TElRRHFSX1EsYmkkMTU4NjM0NTA1MSx3JDApKQ/2/*http://info.yahoo.com/relevantads/

http://answers.yahoo.com/;_ylt=AktBtp7N_YwRzBfViJHU6sYAxgt.;_ylv=3

http://answers.yahoo.com/dir/index;_ylt=AnPK1B1n9gecSd7UOnt5h.kAxgt.;_ylv=3

http://answers.yahoo.com/dir/index;_ylt=AlbMtSz4j.KKqaYW.s.7agIAxgt.;_ylv=3?sid=396545122&link=list

http://answers.yahoo.com/dir/index;_ylt=AnE9CnDhL0e95IPFC1NvpQAAxgt.;_ylv=3?sid=396545219&link=list

http://answers.yahoo.com/question/report;_ylt=AnTpBGy6LsJ5VPznCm27NWgAxgt.;_ylv=3?qid=20090227003212AAh70Ct&kid=NcxEIEj.CjlUkJl5khvT&date=2009-02-27+00%3A32%3A12&.crumb=8yEfuLg2XXs&s=q

http://answers.yahoo.com/my/profile;_ylt=Ap4INJMtOklS54IuG2oYdRoAxgt.;_ylv=3?show=A8ZJJrk9aa

http://answers.yahoo.com/my/profile;_ylt=AgIe7ssv7bJky1MfYh3bNsEAxgt.;_ylv=3?show=A8ZJJrk9aa

http://answers.yahoo.com/answer/report;_ylt=Ark85..jgMkS0kWnnsiMs9MAxgt.;_ylv=3?qid=20090227003212AAh70Ct&kid=LpknAnb.BEmE7yuoA8UI&.crumb=.8yEfuLg2XXs

http://answers.yahoo.com/my/profile;_ylt=AgtzHWWtUU2KOQXbtp6XTbAAxgt.;_ylv=3?show=Zm9htreIaa

http://answers.yahoo.com/my/profile;_ylt=AvVGAvKEILtABfp0sRV9iHIAxgt.;_ylv=3?show=Zm9htreIaa

http://answers.yahoo.com/answer/report;_ylt=AsUjuzuoUUeouRmptAEXK1QAxgt.;_ylv=3?qid=20090227003212AAh70Ct&kid=A75KGWvqFGeqGRVNRAVc&.crumb=.8yEfuLg2XXs

http://answers.yahoo.com/my/profile;_ylt=AolrkIeXpj3pVNz0II3mYzwAxgt.;_ylv=3?show=wJTsifugaa

http://answers.yahoo.com/my/profile;_ylt=As5ij1KKnSNv.6ez_2oRJggAxgt.;_ylv=3?show=wJTsifugaa

http://us.lrd.yahoo.com/_ylt=AmwUD3Tra2Op1xh_8XCS4qkAxgt.;_ylv=0/SIG=15o54nvig/EXP=1357322467/**https%3A//edit.yahoo.com/config/eval_register%3F.src=knowsrch%26.intl=us%26.lang=en-US%26.done=http%3A//answers.yahoo.com/question/index%253fqid=20090227003212AAh70Ct

https://login.yahoo.com/config/login;_ylt=AoyzdcYLNpTnkY4U12HEjfIAxgt.;_ylv=3?.src=knowsrch&.intl=us&.lang=en-US&.done=http://answers.yahoo.com/question/index%3fqid=20090227003212AAh70Ct

http://us.lrd.yahoo.com/_ylt=AombZDO725hnpuOXx.QMm1AAxgt.;_ylv=0/SIG=11t8fupvc/EXP=1357322467/**http%3A//help.yahoo.com/l/us/yahoo/answers/

http://us.lrd.yahoo.com/_ylt=AhxTknmryfJACtSXICLQTmIAxgt.;_ylv=0/SIG=11jrb23pj/EXP=1357322467/**http%3A//overview.mail.yahoo.com/

http://mail.yahoo.com/;_ylt=Aq3hAcyY1uF_rCZECGF5.EMAxgt.;_ylv=3?.intl=us&.lang=en-US

http://my.yahoo.com/;_ylt=AncP7XaxSME6rYnXcLGu3PcAxgt.

http://us.lrd.yahoo.com/_ylt=ApL9GDo6P30q7BVl1Sk0MdoAxgt.;_ylv=0/SIG=119k2fplh/EXP=1357322467/**http%3A//www.yahoo.com/

http://answers.yahoo.com/question/index?qid=20090227003212AAh70Ct#yuhead-search

http://answers.yahoo.com/;_ylt=AnC.qroqCHr2LfdZMJ8iT0UAxgt.;_ylv=3

http://answers.yahoo.com/question/index?qid=20090227003212AAh70Ct#

1/3/13 What's the enthalpy of f eed water at 50 C? - Yahoo! Answers

2/2answers.y ahoo.com/question/index?qid=20090227003212AAh70Ct

oeman50

http://answers.yahoo.com/my/profile;_ylt=AolrkIeXpj3pVNz0II3mYzwAxgt.;_ylv=3?show=wJTsifugaa

http://answers.yahoo.com/my/profile;_ylt=As5ij1KKnSNv.6ez_2oRJggAxgt.;_ylv=3?show=wJTsifugaa

what's the enthalpy of feed water at 50 c_ - yahoo! answers

Documents