PDA

View Full Version : Building diversity



mchild
11-03-2008, 04:58 PM
I am curious on how to determine and measure building diversity in order to properly size the comfort system. What factors are taken into consideration?

I have seen equipment sizing software that can factor in the percentage of diversity for cooling and heating, but don’t know how to determine what it is.

I have done a careful load calculation to determine the maximum cooling and heating required on a room by room basis. Can I extract information from that to determine the diversity?

Thank you.

Danny11
11-03-2008, 06:54 PM
Theres loads of guides on the web.if you can't find any.

Theres a very simple guide on: http://www.airconsquad.co.uk/#/introduction/4523595611

Good luck

mchild
11-03-2008, 08:10 PM
Theres loads of guides on the web.if you can't find any.

Theres a very simple guide on: http://www.airconsquad.co.uk/#/introduction/4523595611

Good luck

Thank you Danny11 but all I could find on that site was a basic load calculation formula.

As I stated I have completed a very detailed load calculation, but I am now wanting to understand the impact of diversity. I understand that to mean the differences within the building on the required load. As an example, the west side of the building in warm weather would need more cooling than the east side in late afternoon. The load on each part of the building will be different at different times of the day.

nike123
11-03-2008, 08:58 PM
Visit this site, it is ,maybe, what are you asking for.
http://www.doe2.com/equest/

mchild
11-03-2008, 10:23 PM
Visit this site, it is ,maybe, what are you asking for.
http://www.doe2.com/equest/

Thanks nike123, I'll check it out.

frank
11-03-2008, 10:37 PM
You determine electrical diversity yourself based on all the information from the end user.

What diversity really means is the 'down time' when some equipment will not be used.

for instance, say you have a 100 amp incoming electric supply available for the property. You would expect then that you could not connect any equipment in the property that, totally, have a combined current draw in excess of 100 amps or you blow the fuse.

Using diversity, you can. If the electric water heater draws 50 amps but is only on for short periods, then you can have other equipment running when the water heater is not on (thermostat satisfied). By juggling the equipment running currents against time you can have equipment rated more than 100 amps total current connected to a 100 amp supply.

The Air Conditioner will not be on 24/7 so you can factor diversity in.

You need to sit down and list all of the equipment in the property and write down the max running currents of each and then create a spreadsheet of when each one will be used, against time, so that you can see the 'total' current draw at any particular time., ensuring that you design within the electric supply rating.

wambat
11-03-2008, 11:00 PM
Equipment sizing for a system can utilize Cooling Load Diversity. Diversity is described as the actual amount of cooling needed (heat load), by various sections of a structure at a given time. Conventional air conditioning systems are designed for the highest structure heat load. The conventional system determines and selects equipment based on the peak heat load demanded by the structure. A system sized to take advantage of diversity would determine the heat load by the time of day, building exposure, and usage. As an example: the sections of a structure facing west, demand more cooling in the afternoon, than sections facing east. The opposite of this is true in the morning, where the east section is exposed to a higher heat load requiring more cooling. Utilizing diversity the cooling system would adapt to the needs of each side of the structure during peak demand by delivering more cooling to that area and less to the areas that do not need it. A structure utilizing a conventional system, requiring 8 tons of cooling at peak load, could utilize a much smaller capacity system (potentially 4 or 5 tons) if the system installed could take advantage of load diversity, which would supply the necessary amount of cooling to the spaces, as and when needed instead of keeping a larger capacity available at all times

mchild
12-03-2008, 12:33 AM
Equipment sizing for a system can utilize Cooling Load Diversity. Diversity is described as the actual amount of cooling needed (heat load), by various sections of a structure at a given time. Conventional air conditioning systems are designed for the highest structure heat load. The conventional system determines and selects equipment based on the peak heat load demanded by the structure. A system sized to take advantage of diversity would determine the heat load by the time of day, building exposure, and usage. As an example: the sections of a structure facing west, demand more cooling in the afternoon, than sections facing east. The opposite of this is true in the morning, where the east section is exposed to a higher heat load requiring more cooling. Utilizing diversity the cooling system would adapt to the needs of each side of the structure during peak demand by delivering more cooling to that area and less to the areas that do not need it. A structure utilizing a conventional system, requiring 8 tons of cooling at peak load, could utilize a much smaller capacity system (potentially 4 or 5 tons) if the system installed could take advantage of load diversity, which would supply the necessary amount of cooling to the spaces, as and when needed instead of keeping a larger capacity available at all times

Yes, wambat, this is what I am seeking. Is there a way to adjust the maximum cooling load to factor in that diversity? Is there also a diversity factor for when the structure is experiencing heat loss?

The program I referenced in my original post allowed for percentage adjustments in both cooling and heating modes for diversity. While I can understand the impact of diversity during hot periods, I can't really see how it would happen during cold periods.

Thank you.