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How to size a commercial water heater

How to size a commercial water heater by Flexiheat UK; industrial water heating sizing;

How to size a commercial water heater past Flexiheat UK

A commercial h2o heater is required for supplying warm or hot potable water for showers, bathrooms, kitchens, restaurant sinks, washing machines etc and other purposes in a commercial or industrial building, such as schools, hotels, gyms or hospitals. A commercial water heater uses electric elements or a burner to rut common cold water upwardly to the desired hot water temperature which is used when a need is placed on h2o heater. Water heaters may utilise a tank to store the heated water for when it is required. Sizing a commercial water heater is relatively piece of cake process and not a " dark art " every bit some people may think.

They are also used in many industrial water heating applications, when hot water is required for a production process, such as commercial laundries or other uses, as office of manufacturing a product or service.

If y'all size or select a commercial water heater with more than the chapters required, you'll finish up with higher uppercase cost and besides higher fuel bills than required, on the other hand If you undersize a commercial water heater, and then you run the take a chance of running out of potable hot water, and upsetting your customers in the case of a hotel for example or your production process declining in the event of a hot water process application. Thus, we have written this "How to size a commercial water heater" guide to help in the correct selection for your h2o heater requirements.

Commercial water heater definition

A water heater can be divers as a closed tank used to supply potable hot water, which is either heated by electricity, gas (Natural gas or LPG), or any other source, such as solar. The water heater is intended to be supplied with beverage h2o either from a potable water supply, such as direct from the water mains system (these are referred to as unvented hot water system) or via feed tanks when used in an open vent hot water system.

The three vital elements to bear in mind when sizing a h2o heater for commercial or industrial applications

Water storage tank capacity: The tank or vessel capacity for storing the hot h2o required. The tank allows a large volume of h2o to be drawn at flow rates that can exceed the recovery chapters of the water heater- which is useful for tiptop hot water demands.

The recovery rate: The amount of water in litres per hour, raised at a given water temperature ascent and kW input. As well frequently quoted is the ane hour describe chapters of the water heater, which is the maximum hot water production for one hr, normally required at the peak period of the day when the heaviest requirement of hot water volition occur.

The power or energy input of the h2o heater – The amount energy required, normally measured in Kilowatts consumed by the water heater, which is provided by your preferred fuel, either electric, gas or oil. 1 kW of energy is 3,412 Btu's, if you use the old imperial system.

These three factors are used together to select the correct water heater size and power rating.

The best method for selecting a commercial or industrial water heater is on the basis of hot water usage. The selection is a combination of these factors of tank size, recovery charge per unit and oestrus input.

What size water heater do I need calculation for commercial h2o heating applications

Following is the European standard for hot h2o demands to DIN 4708, that is unremarkably used when sizing your commercial water heater or industrial h2o heater- whichever you lot may classify your water heater as.

Commercial Edifice Blazon	Demand factor	Bath tub	Shower	Bidet	Private wash basin	Public wash bowl	Kitchen sink	Slop sink	Bar sink
Hotel & Hostels / B&B'due south	0.5	50	50	x	x	xv	fourscore	50	100
Hospital	0.7	60	seventy	x	10	15	80	50	–
University	0.eight	–	220	–	5	25	80	40	–
Restaurant	ane	–	–	–	v	25	140	100	100
Sport middle / Gym's	ane	–	220	–	five	xv	80	xl	100
School (Twenty-four hours type not boarding)	0.eight	–	180	–	5	xx	80	40	–
Manufactory	one	–	120	–	5	20	80	50	–
Commercial Offices	1	–	–	–	5	10	40	40	–

Calculation example for a commercial h2o heater hot water demand

A Hotel with 100 rooms = Litres of hot water / Hour at 60 °C

100 Bathroom tub / showers = 5,000
25 Bidets = 250
100 Private wash basins = 1,000
20 Public wash basins = 375
5 Bar sinks = 500
viii Kitchen sinks = 640
5 Slop sinks = 250

This gives the states a total hot water demand of 8,015 x the need factor for a hotel h2o heating system sizing of 0.5 = 4,007.5 litres per hour continuous at lx °C

With a commercial hot water requirement / awarding like this, due to the volume of water required, the only applied solution is a commercial storage h2o heater, we practise a full range of commercial gas h2o heaters, that we can match to various storage volumes of up to 5,000 litres in a single storage tank ( more when used in series) and a power input of 300kW. They are also condensing too, thus you'll have the maximum efficiency for your hot water commercial arrangement.

We as well supply commercial h2o heaters powered by an oil burner, and this range of oil fired water heaters is fuelled past gas oil which is the preferred oil used in commercial and industrial water heating applications.

As well as electrical powered which we speak in more depth below in this webpage

Hot h2o demands for flat blocks with a communal / centralized hot water arrangement

A standard apartment or flat according to DIN 4708 is defined as consisting of 4 rooms, with 3 /four persons living there, a 150-litre bath (with a fill time of x minutes) with 1 wash basin and one kitchen sink.

It too specifies, within the standard, that the hot water storage capacity and the functioning of the heat exchanger in terms of efficiency are both pregnant factors in determining the number of apartments a water heater or heaters can serve. A full general guide is as follows –

Number of apartments	continuous requirement (litres per hour)
Domestic Hot Water Temperature	60 °C	45 °C
50	3000	4300
100	5200	7500
150	7200	10400
200	9100	13200
250	10700	15500
300	12000	17400

Commercial electric water heater sizing

You size a commercial electric water heater, on the exact same principles as a gas or oil powered version, just the fact that you require electricity every bit the fuel source or ability for the water heater.so employ the above information to establish your hot water requirement, so wait at our webpage commercial electrical water heaters, for the available sizes and power outputs than we tin supply. Just make certain yous accept the Amps bachelor to power the unit.

Commercial tankless water heater sizing

Sizing a commercial tankless water heater is a dissimilar case, as a commercial tankless water heater heats up h2o on need rather than storing warm water in a storage tank for afterward use. This ways they are mostly more efficient every bit they only always heat as much water as you demand and are smaller in size than storage h2o heaters.

Simply they have a down side as heating water on demand requires using a larger burner in the case of a gas or oil-fired commercial water heater or electrical heating elements than a commercial storage h2o heater would use, which ways that the free energy demand while heating the h2o tin be very high. So, you accept to ensure you have the power bachelor to satisfy this requirement.

The most common commercial tankless h2o heater is gas powered, equally gas ( either natural gas or LPG gas ) is nifty at producing a lot of energy via a relatively small supply pipe.

You size commercial tankless water heaters via the number of hot water outlets they take to satisfy, and to what h2o temperature, we become more into this on this dedicated webpage – gas multipoint h2o heaters, that are used in commercial tankless hot water systems.

Industrial water heater sizing / calculation

Often industrial water heaters, are sized in a slightly unlike method, as normally, there are different water temperature rises, specifically required for the process in question
For industrial h2o heating processes, there are normally 3 elements to sizing your water heater.

These are –

1. The volume of hot water that y'all require – How many litres of hot / warm water do you crave?
2. The temperature rise that you lot desire that water to go through due east.g., from the incoming water temperature of 10 degrees C to lxx degrees C etc
iii. Lastly your time requirements – how quickly do y'all want that water to estrus up in, or how many litres yous crave of water per 60 minutes your process requires.

When you have established these factors, then you tin apply the post-obit calculation to establish the kw rating required for you water heater
To heat a specific volume of water past a given temperature rise in ane 60 minutes.

Volume of h2o in litres x iv 10 the temperature rise in degrees centigrade divided past 3412

(only for note – 4 being a cistron and 3412 being a given abiding)

Thus, for a i,000 litre h2o heater, the calculation would be equally follows –

1000 litres of water, to exist heated from say 10°C to 70°C, giving a temperature ascent of 60 °C would consequence in-

i,000 x 4 x 60 / 3412 = 70.339 kW per hr

This means that the g litres of h2o would be heated in one hour by 70.33 kW of applied rut, for the temperature rise of 60°C, whether its past gas, oil or electric

We can utilise this consequence to conclude other factors – e.g., to rut the same water volume of 1,000 litres in half the time (i.e., thirty minutes) we would demand twice the heating power i.e. 140.66 kW, as lxx.339 x ii = 140.66 kW.

Should the process crave a 2-hour period recovery flow for the industrial water heater, then we tin can lower the ability input to 36.xvi kW
When sizing an industrial water heater and for a commercial water heater, these are the actual power input figures into the water heater, and so you demand to ensure that the heater has a nett input of this figure, but its also prudent to add a small-scale percentage for standing estrus losses, if you are using a storage water heater.

Alternatively, if you accept a specific water temperature rise, and you know the kW input rating of the unit of measurement, and so you can summate the water menstruation rate produced, and then use the flowing formula –

m (kg/s) = P (kW) / the specific heat of water (Kj / Kg ºC) X ΔT of the water in Degrees C

Whereby –
m = mass menses rate (kg/s) this is litres per second as one litre of water weighs ane kilogram
P= Power in kW
Specific heat of water = iv.187 Kj/Kg ºC
ΔT = temperature increase in C

An instance
A water heater, with thermal ability input of seventy kW, with a temperature rise of sixty degrees C then it would exist –
yard = (70kW) / ((4.187 kJ/kg ºC) (60ºC))
thus – 70 / 4.187 x 60
70/251.22 = 0.2786 kg/s or 0.2786 Litres a second – times this past 60 seconds to get per minute so past threescore minutes to get the volume per hour – thus 1,003 Litres per hour for a 60 Degree C water temperature rise.

Hopefully this sizing / calculation guide for commercial and industrial water heating applications has provided the information and formulas to help you size the correct water heater for your awarding. Should you require any more than information on our h2o heaters, delight don't hesitate to contact us at Flexiheat Uk