School Heating Question -- Does This Make Sense?

Adding to Lyn, - On the PM side, turning off at 3:PM or thereabouts would save equally on that side, - no use leaving a warm classroom to cool down all night, unless one had some sort of heat storage. (sounds unlikely.) G

I guess that would depend on the insulation of the building. Maybe a lower temp would be better like 50 degrees.

It depends on the thermal inertia of all the construction materials, together with the thermal conductivity of the insulation. There will probably be an optimum of some turn-down at night, with recovery early enough in the morning for comfort when school opens. It sounds as though the present policy is ill-considered.

Of course, they could just turn the thermostat down to 54°F all the time, and feed the kids jumbo soft drinks and sugar bombs. Calvin would just love this.

As usual Lyn has come up with the most logical answer; turn the heat on a couple of hours before classes start. Isn't this what we do at home?

Any windows in the building should be covered with blinds at night to prevent heat from radiating out. Windows are notorious for heat loss, so unless the windows are the latest triple-layer E-windows, it's likely that the cool-down during the night can be minimized using blinds.

Since the main controlling factor is monetary, the cost of heating could be reduced by improving the efficiency...This takes a professional on site to do a thorough evaluation...Insulation gives the most bang for the buck in my experience....When you are working with a budget, you can address efficiency and comfort issues in context...So the first thing is to establish what the budget is....Then you start with the lowest cost tweaks to improve efficiency...Once you have achieved savings by improvements in fuel usage you can use that money to further improve performance, and so on...Possibly raising the humidity to enhance comfort...Alternative sources of fuel may be a possibility...or additional fuel monies acquired by alternative means, donations, bake sales etc....

Quite. A detailed energy audit would point out a number of potential improvements.

All previous comments are good but there is another angle that might be considered. If you use a temperature logger then you potentially have evidence to challenge the implementation of policy. There probably are health codes and possibly OSHA or other laws that prevent us from freezing our school children. Without a log it is easy for an administrator to view the thermostats being set at 68 an hour before class as being ok. When provided with proof that the children are exposed to 50 degrees then everything might change.

I don't recall for sure the USB interfaced logger that I use at work. Mine are very, very nice but we paid about $250 each for them. A Google of "USB Temperature Logger" yielded several different offerings in the $45 to $55 range. I suspect they are all good enough for your application.

It might be an interesting news story for the local newspaper or TV station to put loggers on children for a week. It all depends upon the media in your area. Some are very human interest oriented. Some are very afraid of bucking the establishment.

A final word of warning. Sometimes it is easiest for an administrator to get rid of a problem by getting rid of the person that puts the problem on the administrator's desk. It will start warming up in about 8 weeks. Be careful.

wont work, the best they could do is have an hour "warm up" before the building is expected to be occupied. Their energy management system should have that built in to it....Programming it is another issue!

Stupid or not, you will not convince anyone without data presented in front of the proper authority. Go to the next board of Ed public meeting and ask for data to be presented by the principal showing fuel consumed prior and after to this policy being implemented. I recommend that you also verify if your state or county laws mandate a minimum temperature for occupancy of a public building. Having the data that this principal only believes that this practice will save fuel and is not tracking the result will speak volumes.

If the School Authorities' main aim is to save on fuel Bills + Comfort to students :

They should hire Control System Expert to innovate on the control mode.

Automatizing is a must.

Switch on Heating at 0530 to target 72 degrees. Switch off at 0645.

Warm Welcome to Kids.

And control system takes over at 0730.

Switch off at 1630 Hrs .

Chebycheff's Postulates!

How about heated bulletproof vests? Just sayin.....

Nice analogy.

Hell, if one is only concerned about saving money...turn off the heat and tell the kids to bundle up, bring their own lunches to school, etc.

Better yet, shutter the schools...that would save a ton of money!

Just about the sole purpose of the climate control system is for the comfort of the occupants of the school. If the administration wants to mandate a heating and cooling scheme, I suggest mirroring the one at the district offices. Do they suffer through the same cycles as their student charges?

Try this one: A 200' x 200' building on a slab with 35 air to water heat pumps that had major insulation and air infiltration problems.

Put thermostats in each zone with mechanical timers. Idea was the mechanical times could enable heating when someone needed it after hours.

Now put the whole system on a timer. Enable in the mornimg and off in the evening.

And for giggles, put two heat pumps in one of the rooms with two thermostats independently controlling each heat pump. Brilliant!

The building could never recover, so the innovative energy saving bypass system had to be scrapped.

The contractor did some unusual things. Another example is How to pour an isolated slab: Pour everything. Break up the isolated section. Pour the isolated section.

IF there is any insulation on the walls, it may be on the inside or on the outside. If it is on the outside, the cinderblock's mass is included, if on the inside it is excluded from the heated mass storage.

In my guesstimate the numbers may play out like this for winter at your location:

1,. Fallback temperature 50F, with a heater of 50% reserve at 68F (20F external)

2,. Turn up to 70F an hour before school for internal insulation, 2 hours for external insulations.

3,. The thermal mass of the external insulated needs much less energy to keep comfortable ambience during the day.

4,. You will need to measure the temperature of the walls, not the air. The comfort is largely established by radiation from these surfaces.

5,. Administration wants simple answers to complex problems they do not grasp. They get testy to real answers, as it would unmask their ineptitude. As if that would not be obvious from the beginning, and acceptable.

Never mind. Technically it is simple to medium. Human frailties complicate.

Experience, and adiust accordingly.,

You need a scientist, not an engineer, for this kind of problem. What you need to do is get the building to a stable known temp, say 40°F. Then set the thermostat to say 60°F. Monitor the systems operation determining the amount of actual run time to achieve that temp. Now you have a base line for delta temp for runtime. Easier would be to put a logging device on the system and record the runtime and the temp. Either way you now have the needed data to calculate the most efficient programming for your school. BUT, the best way of all is to simply buy a controller that does all of this for you. There are several good systems designed to achieve maximum efficiency, and all you need to do is replace the existing thermostat/s with one these "eco" thermostats!

Do you know where we can find a scientist?

Any small dark room in the basement of Texas A&M!

Handy and all, you may want to compare the NC academic school test scores, prior to and after the temperature change was placed in effect. You may be surprised at the increase in academic attentiveness and scores.

Codemaster, I agree with your experience and for highlighting that comfort is not necessarily related closely to temperature alone.

It probably does cost less to maintain 68°f if the room is cold at night as there will be less heat lost through the walls at night. However, the rooms are probably not reaching 68°f for much of the day, if at all. So if you are to feel comfortable in the day you may need to feed the lost heat into the walls by using a higher air temperature (and heat output) at the start of the day or the 'cold radiation' felt by spending all day heating the walls and fixtures will leave people feeling cold. That will need a smart controller.

We must also remember that it costs money just to heat the system every morning and that heat is probably lost to no one's benefit after the school closes.

At my home leaving the heat on all night disturbs our sleep, so off at night for a good rest then start the heater two hours before the first person rises because a later start means we feel cold all the time we are getting ready to go out, in which case we are wasting our money on the heating because we don't feel the desired benefit. If the weather gets very cold then the heat is left on all day rather than just morning and evening, for the same reason. In the end it costs more but we get something for our money so it is a personal choice - provided you have the money - and I guess the school doesn't.

If the school only wants to meet its financial targets then it is doing the right thing.

If the school wants the pupils to have an enjoyable and satisfying experience at school then perhaps it should have the cake sales etc. to raise money for school comfort or save money for heating by cutting back in other areas instead. Basically, they need a bigger budget but that ain't likely to happen!

Yes, they will save money but at what cost to the pupils?

Another approach would be to find a temperature setting that burnt the same amont of fuel with the heat on night and day, then see if the school felt more or less comfortable. One would need two weeks of comparable climate (wind, day temperature, night temperature, humidity etc.) to do this well and that is not going to happen, at least, not to order. . . .