Previous in Forum: Insulation Piercing Connectors (IPC)   Next in Forum: Pipeline Corrosion Control Voltage Measurements
Close
Close
Close
28 comments
Associate

Join Date: May 2011
Posts: 27
Good Answers: 2

School Heating Question -- Does This Make Sense?

12/31/2012 3:42 PM

My daughter is a teacher 's assistant in a kindergarten class in central North Carolina. Her school district has established a maximum temperature policy in the school of 68 degree Fahrenheit during winter days. They shutdown all heat for the building [2 story concrete slab building with cinder block walls-roughly 600 students] at 5 PM and leave heat off until about 7 AM the following morning. Obviously the classrooms are very cold when they arrive and it takes until late morning or later to reach the 68-degree mark [kids wear coats most of the day]. My gut says they would save or break even on heating cost if they just maintained a constant 68 degrees throughout the day and night. Opinions?????

__________________
Those saying something is impossible should not interrupt the person who is doing it --- Bernard Shaw
Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
3
Guru

Join Date: Oct 2008
Posts: 42296
Good Answers: 1662
#1

Re: School heating question -- does this make sense??

12/31/2012 3:49 PM

Suggest turning the heat on at 5:00AM.

School policy may mandate 68°, in which case it's up to the parents of the children to insist that the building be made bearable.

Register to Reply Good Answer (Score 3)
Power-User

Join Date: May 2008
Location: Malanda, Australia
Posts: 117
Good Answers: 1
#16
In reply to #1

Re: School heating question -- does this make sense??

01/01/2013 2:19 AM

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

__________________
Let's try and think clearly when looking at information and only allow emotions when weighing up options.
Register to Reply Score 1 for Good Answer
Guru
Engineering Fields - Mechanical Engineering - New Member Fans of Old Computers - TRS-80 - New Member Popular Science - Weaponology - New Member Safety - Hazmat - New Member Hobbies - Fishing - Fish On! United States - Member - New Member

Join Date: Apr 2012
Location: Detroit MI, USA
Posts: 2497
Good Answers: 269
#2

Re: School heating question -- does this make sense??

12/31/2012 3:49 PM

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

__________________
How we deal with death is at least as important as how we deal with life. --CAPTAIN KIRK, Star Trek II: The Wrath of Khan
Register to Reply
Guru
Technical Fields - Technical Writing - New Member Engineering Fields - Piping Design Engineering - New Member

Join Date: May 2009
Location: Richland, WA, USA
Posts: 20981
Good Answers: 781
#3

Re: School heating question -- does this make sense??

12/31/2012 3:56 PM

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.

__________________
In vino veritas; in cervisia carmen; in aqua E. coli.
Register to Reply
4
Guru
Hobbies - Fishing - New Member

Join Date: Jun 2008
Location: Raleigh, NC USA
Posts: 13529
Good Answers: 467
#4

Re: School heating question -- does this make sense??

12/31/2012 4:15 PM

It doesn't make sense to me.

Those concrete blocks hold the cold, so the furnace is going to work harder, warming up the buildings. I would turn it down to 60 at night.

I think it will cost them less money to keep all of that concrete at a relatively stable temperature.

I also think that doing an energy audit on the various schools in the district, and determining the best method and temperature for each, would be a great project for some of the high school science classes.

__________________
Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety. Ben Franklin
Register to Reply Good Answer (Score 4)
Guru
Technical Fields - Technical Writing - New Member Engineering Fields - Marine Engineering - New Member

Join Date: Sep 2008
Location: Vancleave, Ms about 30 miles inland from Biloxi and the coast
Posts: 3199
Good Answers: 105
#5

Re: School heating question -- does this make sense??

12/31/2012 4:16 PM

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?

__________________
Mr.Ron from South Ms.
Register to Reply
Guru
Engineering Fields - Optical Engineering - Member Engineering Fields - Engineering Physics - Member Engineering Fields - Systems Engineering - Member

Join Date: Apr 2010
Location: Trantor
Posts: 5363
Good Answers: 646
#6

Re: School Heating Question -- Does This Make Sense?

12/31/2012 5:18 PM

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.

__________________
Whiskey, women -- and astrophysics. Because sometimes a problem can't be solved with just whiskey and women.
Register to Reply
Guru

Join Date: Mar 2007
Location: at the beach in Florida
Posts: 31273
Good Answers: 1733
#7

Re: School Heating Question -- Does This Make Sense?

12/31/2012 8:09 PM

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....

__________________
Break a sweat everyday doing something you enjoy
Register to Reply Score 1 for Good Answer
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 30407
Good Answers: 819
#26
In reply to #7

Re: School Heating Question -- Does This Make Sense?

01/02/2013 7:50 AM

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

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Guru

Join Date: Jul 2008
Posts: 1558
Good Answers: 138
#8

Re: School Heating Question -- Does This Make Sense?

12/31/2012 8:37 PM

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.

__________________
Few things limit our potential as much as knowing answers and setting aside questions.
Register to Reply
Guru

Join Date: Feb 2011
Posts: 7045
Good Answers: 206
#9

Re: School Heating Question -- Does This Make Sense?

12/31/2012 9:20 PM

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!

Register to Reply
Guru
Engineering Fields - Electrical Engineering - Been there, done that. Engineering Fields - Control Engineering - New Member

Join Date: Dec 2008
Location: Long Island NY
Posts: 15179
Good Answers: 937
#10

Re: School Heating Question -- Does This Make Sense?

12/31/2012 10:06 PM

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.

__________________
"Don't disturb my circles." translation of Archimedes last words
Register to Reply
Guru
Engineering Fields - Systems Engineering - New Member Hobbies - Model Rocketry - New Member

Join Date: Dec 2006
Location: Long.92E,Lat.26N
Posts: 1336
Good Answers: 14
#11

Re: School Heating Question -- Does This Make Sense?

12/31/2012 10:59 PM

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!

Register to Reply Score 1 for Good Answer
Active Contributor

Join Date: Jun 2012
Posts: 20
#12

Re: School Heating Question -- Does This Make Sense?

12/31/2012 11:38 PM

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

Register to Reply Score 2 for Off Topic
3
Power-User

Join Date: Jun 2009
Location: Australia
Posts: 277
Good Answers: 45
#13

Re: School Heating Question -- Does This Make Sense?

12/31/2012 11:38 PM

Most seemed to overlooked answering your question and replying at a more operational/comfort related one - You questions was about cost efficiency of switching the power off in lieu of leaving it on. Your gut is wrong in my estimate.

Imagine that the school room was a bucket of water with a hole in the bottom that leaked water out and that the heating system was a small tap that allowed water top drop into the bucket.

A simple equivalent of leaving the heating on would be like leaving the tap on till the water rose high enough for give a head of water to build and force the water out at an equilibrium rate - so giving an equilibrium height (i.e. temperature).

Pretty clearly, switching the power(tap) on and off gives a lower average height of water (temperature) and uses less water (energy) than the continuous approach.

In real life the tap (heater) would be "thermostatically" controlled and so the above analogy would be more complex, somewhat akin to having a double skinned bucket with a leak into the cavity and then from the cavity to outside - but the overall lower average inside level (temperature) from on-off operation would still lead to a lower average loss (water or energy) and so less overall input (of water or energy).

Register to Reply Good Answer (Score 3)
Guru

Join Date: Jun 2011
Location: Phnom Penh
Posts: 4019
Good Answers: 102
#14
In reply to #13

Re: School Heating Question -- Does This Make Sense?

01/01/2013 12:29 AM

Nice analogy.

__________________
Difficulty is not an obstacle it is merely an attribute.
Register to Reply
Guru

Join Date: Apr 2012
Posts: 732
Good Answers: 17
#25
In reply to #13

Re: School Heating Question -- Does This Make Sense?

01/02/2013 1:06 AM

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?

__________________
common knowledge...less common than common sense
Register to Reply Score 1 for Good Answer
Power-User

Join Date: Sep 2011
Posts: 267
Good Answers: 7
#15

Re: School Heating Question -- Does This Make Sense?

01/01/2013 12:55 AM

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.

Register to Reply Score 1 for Off Topic
Guru

Join Date: Jan 2008
Posts: 1753
Good Answers: 59
#17

Re: School Heating Question -- Does This Make Sense?

01/01/2013 2:20 AM

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.,

Register to Reply
Commentator

Join Date: Dec 2012
Posts: 65
Good Answers: 3
#18

Re: School Heating Question -- Does This Make Sense?

01/01/2013 5:36 AM

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!

Register to Reply
Guru

Join Date: Oct 2008
Posts: 42296
Good Answers: 1662
#19
In reply to #18

Re: School Heating Question -- Does This Make Sense?

01/01/2013 8:16 AM

Do you know where we can find a scientist?

Register to Reply Score 1 for Good Answer
Commentator

Join Date: Dec 2012
Posts: 65
Good Answers: 3
#22
In reply to #19

Re: School Heating Question -- Does This Make Sense?

01/01/2013 12:04 PM

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

Register to Reply Score 1 for Off Topic
3
Associate

Join Date: May 2011
Posts: 27
Good Answers: 2
#20

Re: School Heating Question -- Does This Make Sense?

01/01/2013 9:51 AM

Thanks for all of the great inputs to my question. I have shared these with my daughter and she has identified several "paths of action" that hopeful will help the children involved. As always CR4 "engineers" have added perspective and sound observations. Thanks for helping.

__________________
Those saying something is impossible should not interrupt the person who is doing it --- Bernard Shaw
Register to Reply Good Answer (Score 3)
Guru

Join Date: Oct 2006
Location: Surrey BC Canada
Posts: 1571
Good Answers: 40
#21
In reply to #20

Re: School Heating Question -- Does This Make Sense?

01/01/2013 11:56 AM

Do it the Canadian way - students go on strike for warm rooms.

Since compensation is based on the number of student hours, they hit the financial pocket of the school.

But, whoever starts it gets black balled! So be prepared for the backlash.

Register to Reply Off Topic (Score 5)
Power-User

Join Date: Sep 2009
Location: Wilmington, NC
Posts: 140
Good Answers: 8
#23

Re: School Heating Question -- Does This Make Sense?

01/01/2013 12:45 PM

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.

Register to Reply
4
Guru

Join Date: Jul 2005
Location: Stoke-on-Trent, UK
Posts: 4331
Good Answers: 130
#24

Re: School Heating Question -- Does This Make Sense?

01/01/2013 1:10 PM

I agree with your gut and several other posts. First house I moved into when I got married I put the heater on time control, on 0700h so warm whern getting up for work, off 0900h, on 1630h so warm(ish) when we got home. In the winter the boiler would run continuously till about 2130h, then go off on the room stat (~ 70°F) for 1/2 hour, then on again (on room stat), till off on the timer at 2300h, and we never felt warm. I think it was when we had kids started leaving it on continuously, found it cost no more and much more comfortable. Been running heating like that in various houses since, and banging on about it to anybody who'd listen!

It's the "cold radiation" effect. If the walls, furniture etc are cold, the air temperature has to be higher to feel comfortable. With heating on continuously, can turn the room stat lower. Also it must be better for the building to be at fairly steady temperature rather than constantly cycling.

__________________
Give masochists a fair crack of the whip
Register to Reply Good Answer (Score 4)
Active Contributor

Join Date: Sep 2009
Posts: 22
Good Answers: 2
#27
In reply to #24

Re: School Heating Question -- Does This Make Sense?

01/02/2013 11:53 AM

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. . . .

Register to Reply
2
Power-User
United States - Member - US Navy Veteran

Join Date: Mar 2007
Location: Nothing sucks more than that moment during an argument when you realize you're wrong.
Posts: 301
Good Answers: 22
#28

Re: School Heating Question -- Does This Make Sense?

01/02/2013 8:32 PM

If these units are heat pumps with 2 stage heat - it will cost more to turn them off than to turn them down - because when you turn them back on both stages will run for hours which is crazy expensive - and it will register as a spike if they have a peak demand logger triggering a higher surcharge in addition to KW charge for the next calendar year.

__________________
You never know when it will strike, but there comes a moment when you know that you just aren't going to do anything productive for the rest of the day.
Register to Reply Good Answer (Score 2)
Register to Reply 28 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Copy to Clipboard

Users who posted comments:

BruceFlorida (1); Codemaster (1); DAVEWISOR (1); DogOfWar (2); Fredski (1); GW (1); Handy (1); JPool (1); KeepItSimpleStupid (1); kramarat (1); leveles (1); Lookfar (1); lyn (2); markar (1); mog (1); MUKULMAHANT (1); Ptrend (1); PWSlack (1); redfred (1); ronseto (1); SolarEagle (1); The.Tinkerer (1); Tornado (1); TrevorM (1); Usbport (1); Wal (1)

Previous in Forum: Insulation Piercing Connectors (IPC)   Next in Forum: Pipeline Corrosion Control Voltage Measurements

Advertisement