Heating setup for hotel / multiple showers

[skhudy]

I'm helping out a family member with a Hotel they have bought recently.

There's lots of things to get a handle on, but one thing on the horizon is the hot water system. We are going to get some plumbers in, but if anyone here can give ideas it would be usefull.

There are 25 bathrooms / ensuites. 3 electric showers, the rest are fed from some large cold water tanks in the loft and hot water from the 'boiler room'.

The boiler room has an absolutely 'huge' hot water cylinder 4000l i estimate which is constantly kept hot by a single combi. There are 3 floor standing units for the heating. This was put in 40 years ago and I guess may not be the system recommended now.

The pressure in the ensuites is ok, but not great when multiple showers are in use. There are some water pumps in some places where i guess pressure is a problem

What system would be put in place for such a business if it were done from scratch? The gas bills in this place are huge - i guess in the main from keeping the cylinder hot.

 

[Boilerman2]

A suitably sized break tank linked to a Cold Water booster Set feeding a suitably sized Unvented Hot Water Cylinder or perhaps a Rinnai gas fired water heater and buffer vessel - problem with Hotels is that there will be a massive HWS demand twice per day Rinnai might be the best option!

 

[Dan Robinson]

Rinnai water heaters on a boosted supply.

Decent commercial boiler for heating.

Maybe Atag Q XL.

 

[Boilerman2]

I'll bet the Budget won't stretch far enough to do it properly - seen it a million times!

 

[Dan Robinson]

Indeed

 

[skhudy]

what type of numbers would it be to do it properly? with 6k pa gas bill and the turnover of the business it probably will be done but a guesstimate would be good. thanks for replys

 

[Dan Robinson]

Impossible to say on a forum.

All Sorts of considerations including legionella and TMV3

 

[Agile]

I would say perhaps £15k to £35k.

But unfortunately what people do is say they cannot afford a proper system and put in a bodge. Already a bodge is on the cards as you are asking here rather than paying someone to visit and design a system.

It is unlikely the gas bill is high because of any heat loss from the cylinder. That is likely to be less than 1% of the bill. It will just be the cost of heating and hot water. Its actually cheaper than I would have expected.

Dont think improving the system will save gas. People in hotels use hot water when its nice and hot. If not they dont bother!

Tony

 

[skhudy]

Thanks, I thought it should cost at least 20k. I asked on here as I want to have a little idea before getting a pro in for advice! i don't know the area or any tradesman.

The boiler room is very hot, and its used as a drying room for washed towels! there is a lot of heat coming off The cylinder as its not properly insulated.

I would say perhaps £15k to £35k.

But unfortunately what people do is say they cannot afford a proper system and put in a bodge. Already a bodge is on the cards as you are asking here rather than paying someone to visit and design a system.

It is unlikely the gas bill is high because of any heat loss from the cylinder. That is likely to be less than 1% of the bill. It will just be the cost of heating and hot water. Its actually cheaper than I would have expected.

Dont think improving the system will save gas. People in hotels use hot water when its nice and hot. If not they dont bother!

Tony

 

[JohnD]

cylinder as its not properly insulated.

I spy the first, simplest, quickest and cheapest job to be done.

 

[Agile]

Yes but they will not want to insulate the cylinder because they use the waste heat for drying.

So one item to be bought is a Loadstar gas drying machine. New one about £1300. Used one about £300 plus moving. They could have one of mine!

They could also have a nice almost new 35 lb Washer to complete their laundry!

Tony

 

[Dan Robinson]

Or they could outsource the laundry contract, and do away with inefficient stored water and heat on demand.

4 Rinnai's with a small buffer would walk this type of installation (not done the maths yet). Could do away with stored water altogether with 5 or 6 heaters.

Gas Supply permitting of course .

 

[Agile]

There are 25 bathrooms, Dan.

So if they all wanted to bath/shower at the same time that could need a DHW flow rate of 250 li/min.

Some mains flow rate and some Rinnais!

I would keep stored water.

 

[Dan Robinson]

That's not how you calculate loading Tony,

And you wouldn't run it straight from the mains.

3 star hotel would be around 35 litres per person per hour (peak) with a 70 - 80% diversity.

Say 50 people x 35 = 1750 litres @ 70% = 1225 litres


56kW gives 16 litres per minutes x 60 = 960 litre per hour.

2 units would run the whole place on showers only @ 6 litres per minute.

Bang a couple more in and that's baths and kitchen dealt with.


Unless I have forgotten the calculation method

 

[skhudy]

The missing insulation on once end of the cylinder is something I'm going to address. Its not a proper "drying room" by any means so it is wasted heat. Gas dryers are on the horizon along with in sourcing the laundry

The Gas pipe diameter is huge, as is the meter - around 65mm diameter (19.5 / 20cm circumference)

The Rinnai's idea sounds very appealing if it could work, and is something I'll see if the local plumbers recommend!