calculating demand

Robertbaker63 · Apr 17, 2015

a local pub i do alot of work for wants to build 6 pod style holiday lets in its beer garden and has applied to western power to see if the existing supply can cope with the demand
the existing supply is 2 phase with a 200 amp fuse in each phase leading to a busbar system. ive been asked to calculate for the owner what the maximim demand for these 6 pods will be in total

hes given me the following info

Building requirement: 7.5kw
3.5kw Space Heating
3kw Water Boiler
1kw Lights (LEDs)

Appliance requirement: 8.0kw
1kw Microwave
1.5kw Kettle
3kw Oven
0.5kw TV
1kw Hair Dryer
1kw Iron

for me i'd of said the heater and water boiler are likely to be on at the same time and maybe an appliance or 2 so i'd allow 8kw per pod but 8x6 pods would be 48kw? can i apply any further diversity or is that the figure i'll have to give??

many thanks rob

Plonker 3 · Apr 17, 2015

Why would the water boiler and heater be on at the same?

Will they be occupied all year round?
Will they all be occupied at the same time?

Robertbaker63 · Apr 17, 2015

i'd take a guess at any business wanting to make money would like all 6 let every week 12 months a year but in reality in will be busier in the summer

why wouldnt the hot water be on for a shower etc while they have the heater switched on in the main room?

Leesparkykent · Apr 17, 2015

Dillb said:
Why would the water boiler and heater be on at the same?

Will they be occupied all year round?
Will they all be occupied at the same time?

Maybe because they want hot water and heating on at the same time.

davesparks · Apr 17, 2015

What type of water heater and space heating is it?

Plonker 3 · Apr 17, 2015

Leesparkykent said:
Maybe because they want hot water and heating on at the same time.

But surely the water heater wont be running at 3Kw once it has heated the water up meaning only using minimal power to keep it upto temperature.

Robertbaker63 · Apr 17, 2015

i haven't been told the make/model of anything being used. the information i was given im assuming was supplied to the owner from the manufacturers of these pods. as far as i know these pods arrive complete and i will be just connecting them up. with regards to the water boiler i'd guess at it being an unvented cylinder so they can get a powerfull shower off it

i know the original quote for installing a new 3 phase supply was about 30 grand plus vat which is why their trying to get away with taking supplies off the exisiting 2 phase supply. apart from the kitchen which is mainly kitted out with applainces which use gas bottles and a few electric fryers/plate warmers the pub isnt huge and doesn't pull alot of electric

Leesparkykent · Apr 17, 2015

Dillb said:
But surely the water heater wont be running at 3Kw once it has heated the water up meaning only using minimal power to keep it upto temperature.

Of course it will, every time the thermostat kicks in it will draw 3kw.

Robertbaker63 · Apr 17, 2015

i would agree most of the time there would be hardly any draw but i'm thinking of the times when maybe a group hires all 6, goes out surfing for the day and the first thing the'd do when they came back in an evening would to be to put on the heating and all have a shower/put the oven on

Plonker 3 · Apr 17, 2015

Leesparkykent said:
Of course it will, every time the thermostat kicks in and out it will draw 3kw.

Not for a prolonged period of time though which would affect maximum demand

davesparks · Apr 17, 2015

Robertbaker63 said:
i would agree most of the time there would be hardly any draw but i'm thinking of the times when maybe a group hires all 6, goes out surfing for the day and the first thing the'd do when they came back in an evening would to be to put on the heating and all have a shower/put the oven on

That would be a short term peak load then wouldn't it, not quite the same as the maximum average demand

Leesparkykent · Apr 17, 2015

Diversity - Estimating Total Load - Ted

Robertbaker63 · Apr 17, 2015

thats a good table for calculating demand for a property but i'd end up with 60-80kw using it to the letter of the law depending on how generous i was beiing which seems unrealistic for 6 small holiday pods in the beer garden of a seaside pub

Leesparkykent · Apr 17, 2015

IMO for the immersions you could say allow 100% flc for the 1st two huts then 25% for the other four huts as all won't be on at the same time plus will have thermostatic control etc. then 66% of lighting across all six huts, repeat the process for cookers, heaters etc then divide the final figure by 6 so you roughly know what you will be looking at for each hut.

100% for the sockets in the 1st hut then 40% across the other huts etc

Leesparkykent · Apr 17, 2015

Robertbaker63 said:
a local pub i do alot of work for wants to build 6 pod style holiday lets in its beer garden and has applied to western power to see if the existing supply can cope with the demand
the existing supply is 2 phase with a 200 amp fuse in each phase leading to a busbar system. ive been asked to calculate for the owner what the maximim demand for these 6 pods will be in total

hes given me the following info

Building requirement: 7.5kw
3.5kw Space Heating
3kw Water Boiler
1kw Lights (LEDs)

Appliance requirement: 8.0kw
1kw Microwave
1.5kw Kettle
3kw Oven
0.5kw TV
1kw Hair Dryer
1kw Iron

for me i'd of said the heater and water boiler are likely to be on at the same time and maybe an appliance or 2 so i'd allow 8kw per pod but 8x6 pods would be 48kw can i apply any further diversity or is that the figure i'll have to give??

many thanks rob