Use of reverse return for hotel hot water risers

[darrenlcy]

Hi All,

I have the following questions on the design of central domestic hot water system for one of my ongoing hotel project, this project comprise of 2 area. Area 1 comprise of 6 blocks of hotels each 7 storeys high and area 2 comprise of 6 zones of villas where each zone is made up of about 15 to 20 villas, separate cold and hot water system are provided for two above 2 area. Separate cold and hot water sytem are provided for the above 2 areas:

1. For area 1, if i intended to use reverse return for the hot water return lines, can i do away with balancing valve at the bottom of each hot water return risers (around 12 risers per block )since the system is suppose to be self balancing.

2. For area 2, The current design for the cold water supply is by variable speed pumping from a central water pump room. The hot water to the villas is provided the respective air source heat pump located at each zone. The 6 zones plus the 6 nos of air source heat pumps is served by the same variable speed pumping system. Will there be any issues in the control of the variable speed pumps and do i need to place the balancing valves at the return lines of each villa for balancing purposes.

Thanks.

 

[bobpape]

Because of the nature of water carrying pipes, flow and pressure rates at selected points can not be accurately predicted using theoretical information as you do,

But why bother anyway when all you have to do is fit a few balancing valves

Your main problem surely lies in getting the pipe sizing right,
In my opinion a good plumber would tend to err on oversizing the pipe work if he could
get away with it
Trouble is most developers try to save money any way they can,

Working in the UAE in the 70s I was discussing pipe sizing with the Arab partner of my firm who was building several 4 story apartment blocks.
he said to me "Will water come out of the tap", To which I replied yes but not much, He said thats ok then
most of the prospective users never had taps so they wont know any different,

Sounds like you have an interesting job, what stage is the work at,

Bob