Gotta do a presentation tomorrow for an interview, on overheating buildings.

Its mainly about the engineering options that were considered and those which in turn were implemented in previous employment, which i dont have many examples of.

Any tips?

I am briefly gonna talk about what causes overheating, then onto 3 quick case studies.

We used film on the inside of the glazing as a permanent cheap fix on overheated new classrooms (M&E didnt do the sums right on solar gain)

Are you looking for pre or post construction fixes?

both really!

lots of glazing, lightweight buildings and over insulation to comply with building regs/CFSH means nice greenhouses to live in.

thermal mass helps regulate temperature in glazed buildings.

I’m not an architect, just opinionated..
Generally IMO it’s the unfit majority (particularly the secretaries.. 😐 ) who have such a slow metabolism having spent too long sitting on their bums without excersise, and growing up in centrally heated houses. They get cold below about 25C and complain to management.

Those of us who for ecological reasons or personal comfort prefer much more modest coditions get our regular arguments to facilities drowned out, till we give up trying. I do find shorts are helpful, particularly when it snows which seems to be the worst conditions for our building.

From engineering standpoint, our big building has the usual central air supplies in addition to radiators along the windows. The radiators are “owned” by those who have the benefit of sitting there (mostly in aforementioned categories.. I’m not prejudiced..). The only way to turn them off is to crawl beneath the “owners” desks. This gets a little tricky in an office. Hence they win.

– used stack effect on a central london job with a glazed core to get air movement through the common areas

– used shading over glazing on a uni building in central london (extruded copper so was pretty expensive)

– used ground source heat pumps including running water through the slab to regulate the concrete temperature slightly more than just using thermal mass

– air conditioning???

oh and splitting buildings into zones so that area affected by external/internal conditions (ie south facing areas or plant rooms) are separated from area that do not need so much cooling

Microsoft’s Irish datacentre is pretty cool, it doesn’t use traditional air-con units, it just sucks in air from outside as the average temperature is cold enough. Dunno if it’s relevant to your needs though (datacentres in general must be at the cutting edge of building cooling though).
There’s a better article on it somewhere but could only find this link http://blogs.technet.com/b/msdatacenters/archive/2009/09/24/dublin-data-center-celebrates-grand-opening.aspx

I’ll get flamed for this, but the way in which we design and occupy buildings has changed. We look at tighter envelopes which are pressure tested (in accordance with part L) so that we get no natural ventilation. The density of occupation is huge beacuse land/buildings are so expensive, windows are minimised to reduce solar heat gains so we need more lighting, our IT systems are so much more powerful but also emit a LOT of heat. So, in summary we need air conditioning; ideally designed intelligently with correct zoning and the use of passive chilled beams or the like. I have seem loads of modern buildings have VRF and split systems retrospectively installed. Simplistic and idiotic questions are asked of clients; “can you tolerate 28degC for 2 days of the year?” but the more pertinent questions are “can you tolerate 27degC for a month, 26degC for a few months?” “Can your FM tolerate hourly complaints from the workforce?”. Giving the workforce control of occupied space temperatures is ridiculous. Just take the TRVs off the emitters.

Causes of overheating in buildings:

1) External factors – orientation, solar gain, etc
2) Internal factors – internal heat gains, lack of control

Solar gain on or through the fabric: if its hot outside…

Solar shielding (by solar glazing/film or brise soleil) reduces heat input into the building in summer. Insulation also helps, as does internal thermal mass (i.e. exposed concrete). Night time cooling strategies can be used to pre-cool the building for occupation without air con…

Internal heat gains. If you insist on filling buildings with people and equipment what do you expect… Inefficient lighting, computers, running equipment when not actually being used all generate waste heat. Lighting control systems switch off lighting when not required. Bin all halogen spots as they generate more heat than light. Locate big heat generating equipment (like photocopiers, printers, etc) in one place and extract above it. Select/use efficient equipment…

Controls: zone according to use and orientation. East facing heats up quicker than west in the am before the sun crossed over and the east is colder and the west much hotter… Use optimisation, weather compensation, zone ‘room’ stats to switch off zones that reach a preset temp (say 24 deg C).

Natural ventilation schemes are cheaper to install and run (but difficult to retrofit). They can’t cope with higher external ambients though so depending where you are you will always overheat at some point). Mixed mode to bring on vent/air con only when necessary. Air con as a last resort (usually ‘comfort cooling’ solutions).

HTH

backhander – Part L is to try and stop unnecessary/unwanted air infiltration. The idea is that you control the amount of air ‘whistling’ through a space. If you cant control it then you get draughts… not good in summer or winter.

Doesn’t stop the use designed natural vent systems. This could be as simple as openable windows…

I used to work in this building – the grey bits on the left are flaps that gradually close as the sun came around and shines on that side of the building during the course of the day.

It also had waht they called ‘stored coolth’ in big voids int he floors and roof to help cool it in the summer.

yea i worked in one of those, sealed buildings over the summer , never again, its so horrible,

@FuzzyWuzzy. That Data Centre was/is one of my projects. The external ambient conditions over here are such that we can do without supplemental cooling all year round. It’s first time that the Irish climate has been an attraction!

So, in summary we need air conditioning; ideally designed intelligently with correct zoning

Further to this the internal space should not be changed, introduction of new offices/partitions etc, which will screw up all the hard work that has previously been done in an intelligent way. No tall furniture either which will affect the A/c too.

have you tried opening a window?

Doing a load of Code 6 houses at the moment. We have solar shading whether it be large overhanding eaves or brise soleil’s to minise solar gain southern facing windows, larger windows to improve light quality on northern facing windows. Size of windows is also important. Have an air tightness of 1.

On other schemes we have used solar reflecting glass but not convinced by it yet.

Doing a large job, with underfloor & trench heating, chilled beams and pasivent natural vent with roof stacks, be interesting to see how that all pans out. Natural vent is a big thing now on new builds as are renewables i.e. biomass heating, heat pump and CHP for a dual output.

AOV’s working in conjunction with AC systems works well, I’ve worked with a product from WindowMaster, who have a good product.