In-line Water Heating for Sports Club Showers

waterone

We need to solve a problem in our club
- not enough hot water available for showers
- cost of heating water

We have about 18 shower heads accross several changing rooms, with no more than 10 used concurrently on a regular basis
Water heating is by
- Gas boiler (same as for central heating) + 2 x Immersions - concurrently used

We use showers in club approx 125 days/year.
We could have up to 60/70 people taking showers within a 90 minute period

Has anyone experience of inline water heaters being used in this type of environment?

Would we be better off installing a larger cylinder and larger boiler?

What sort of mains water pressure/flow would be required to satisfy an inline heater in the described environment?

JohnnieK

It sounds like your cylinder has not been sized correctly. Also can you add the size of the boiler in kW's. It is also important at the installation stage to state roughly how many showers per day are expected. And is there more usage on the system now as there was before?

waterone

anyone got any experiences to share in this space?

Carlow52

Its a pity you dont provide some more detail:

From you first post:

- Gas boiler (same as for central heating) + 2 x Immersions - concurrently used

From the only reply thus far:

Also can you add the size of the boiler in kW's

As an answer

anyone got any experiences to share in this space?

could not be construed as being exceptionally helpful in progressing the project.

As a starting point, have you discussed the problem with other clubs in your area.

The math is not hard: you calculate the amount of hot water required and then decide how to heat it.

The scale of the problem came be guessed at from the fact that your average crap electric house shower uses between 9 and 13kW : ie every hour consumes between 9 and 13 kWh of energy.

So you have 10 showers going for 90 minutes which is c 200 kWh of energy which you need to have available.

This energy requirement is why we need to know what the current set up is.

As a starting point, I would have a good quality water meter(s) installed on the hot and cold feeds to the shower rooms to measure the exact usage.

If you know the volume being used and the temp the water is being deliver at

then you can do the math re energy required.
see here:
http://www.engineeringtoolbox.com/specific-heat-fluids-d_151.html

which shows that water requires 4.19 kj of energy per kg per 1 degree rise in temp

dont get phased by units
see here:
http://www.engineeringtoolbox.com/unit-converter-d_185.html

1 cc of water weighs 1 gram and degrees K = degree Celsius

125 days a year: is this spread right across the year or is there a close season: the reason I ask is there needs to be a balance between storing hot water and producing it just as required.

DoneDL

Another option might be to rededicate the cylinder supply for other purposes within the club and fit gas multi-point water heaters to service the showers. You have to consider negating the risk of Lerionaires disease and then finding the most economical way longterm of providing for varying hot supplies to the showers to meet both low and high demand.

slavetothegrind

i would consider 2 x 300 litre twin coil fully insulated high pressure vessels heated by a dedicated gas boiler on a time clock as well as the usual thermostats.

Once you get these up to temperature and there is no draw off them they will lose not more than a degree or three over a 24 hour period (all pipework fully insulated)

So they could store at 75 degrees and would recover fairly quickly ( depends on coils and heat input versus draw obviously)
you would need thermostatic controls to avoid scalding .

There are direct gas fired water heaters in this size but the vessels fail after relatively short periods in service so i would go indirect for that reason.

slavetothegrind

slavetothegrind wrote: »

i would consider 2 x 300 litre twin coil fully insulated high pressure vessels heated by a dedicated gas boiler on a time clock as well as the usual thermostats.

Once you get these up to temperature and there is no draw off them they will lose not more than a degree or three over a 24 hour period (all pipework fully insulated)

So they could store at 75 degrees and would recover fairly quickly ( depends on coils and heat input versus draw obviously)
you would need thermostatic controls to avoid scalding .

There are direct gas fired water heaters in this size but the vessels fail after relatively short periods in service so i would go indirect for that reason.

As above, but I would fit the cylinders in series so you can chose to run one cylinder or both depending on requirements, the reheat time with both coils plumbed is very very quick and the larger the boiler the better the performance as the coils tend to have a large heat output.