how to stop hot water going cold over long distance?

[Ronnie]

hi,
im a building services student and stumbled across this forum whilst researching for a project..

i've designed a system, but one part of the system involves a hot water pipe travelling a large distance, how can i stop the water from cooling?

normal lagging wont work, so what else? some sort of heat tape?

thanks for any help or suggestions you may have..

 

[hj]

Unless you can keep the water moving in a circle back through the water heater, using a second parallel pipe, you can't.

 

[Sponsor]

 

[Jc60618]

A return line with a circulation pump.

 

[Ronnie]

thing is, im already using a return line..
its a commercial building, has 2 wings, east and west..
plant room is in the east wing, so by the time the water travels from east wing to other side of west wing, its gonna be cold..

is there nothing similar to heat tape, or some sort of ******** trace heating?

 

[hj]

If it is circulating at the proper rate, it will NOT be cold, unless it is not insulated at all, in which case you have a difficult problem to solve.

 

[Ronnie]

thanks for helping..
ok, not cold, but surely it would be at a reduced temperature? we're talking like a distance of 50 meters it's travelling from the storage tank..

i hope i havnt misunderstood what you mean.. basically, the hot water comes out of the storage tank, gets pumped and visits all the outlets (in this case hot water taps), and then returns to the bottom of the hot water tank, where there is a thermostat/pump set up, and then flows out of the hot water storage tank, mixes cold water input and enters the boiler..

bit like this without the boilers in series: (if you scroll to page11)

http://docs.google.com/viewer?a=v&q=cache:TE3jGUeEjIkJ:www.bosch.com.au/content/language1/downloads/comm_brochure.pdf+commercial+hot+water+systems&hl=en&gl=uk&pid=bl&srcid=ADGEESjkf1twFlqwuSkihjIfrDyo2hwvg3WWJCBAqlOW0Qi-dPPtPvGcPmudbNV6FDsM-qMmwLmh9fJ7bnXnCyZnG_uh7ZDlknkzfOL27OJXIqBiQOgxNeKc7jTp4Y2aaz8XHC9ImhbA&sig=AHIEtbR7thrPvHz5oN7D_5KNLdRGSYSARw