Ventilation solutions for overheating corridors in apartment buildings

A brief history of Colt A private company founded in 1931 I J O’Hea OBE (1897 - 1984) 2012 Group turnover £151 million Manufactures in the UK, Holland, Germany, Saudi Arabia, China and Brazil I J O’Hea, Colt Founder

Current UK Business markets Smoke Control Solar Shading Natural Ventilation Louvre Environmental Comfort Control By investing in innovation, products, services and people, Colt International has established itself as an international leader in the fields of: Smoke Control Solar Shading Natural Ventilation Louvre Environmental Comfort Control (HVAC) Air Handling Systems

The quest for energy efficiency (ADL and BREAAM) has led to very good sealing and insulation in residential buildings and an increase in district heating schemes. This has unintended consequences for stair lobbies, corridors and entrance halls, which tend to overheat, resulting in unpleasant conditions for residents. Caspian Wharf, a Berkley Homes development, uses a district heating system and therefore overheating in the common corridors was a concern for the design team.

District heating systems distribute hot water to apartments 24 hours a day via insulated pipe work in the corridor ceiling voids. Even with good insulation, enough heat is emitted to cause overheating in the corridors below.

24/7 heat gains, per corridor: Lighting Gains – 3W/m² District Heating Gains - 10W/m² Mechanical Riser – 204W Comms. Riser – 150W Based on 38m² foot print = TOTAL estimated heat load, per corridor 850W

Q: What can you do to avoid heat building up in these common areas? A: Use the existing smoke control system for day-to-day ventilation. The simple solution is to use the ventilation equipment which is already providing smoke control to these areas. Natural or mechanical smoke ventilation systems may be adapted for day-to-day ventilation use. Conclusions

Q: Will you require additional equipment or modifications? A:The answer is dictated by how much temperature control you want If your building has a multiple shaft smoke control system, it can readily be configured to provide day-to-day ventilation with minimal additions. If the building has a single shaft system, you will need inlet air. You could provide it from the stair, using a weathered roof smoke vent. In this case, you will need fire rated smoke dampers between the stair and the corridor. You will need to consider fan noise, as noise levels considered acceptable for emergency use will not be acceptable for day-to-day ventilation use. Conclusions

Day-to-day Ventilation for Apartment Buildings: AOV Systems Environmental Control Requirements – Natural AOV AOV can be used for day-to-day ventilation, but: Ventilation is single sided, has no separate inlet, has poor temperature control Is lobby geometry and vent location suitable? Potential for hold open devices on cross corridor doors for through flow? Consider finger trapping Control requirements: Wind, Rain..

Day-to-day Ventilation for Apartment Buildings: Natural Shaft Systems Environmental Control Requirements – Natural Shafts Natural shafts can be used for environmental ventilation, but: There is no permanent air inlet unless specially provided Is lobby geometry and vent location suitable? Risk of cross contamination between floors Motorised doors have issues with finger trapping and access to the shaft Control requirements Rain Sensor?

Multiple Shaft Smoke Control System Supply Extract Corridor Smoke Damper & Grille for inlet/exhaust Conclusions Smoke Extract Fans for supply/exhaust

+ + + Multiple Shaft Smoke Control System – additional requirements Corridor Temperature Sensor + Variable Speed Drive for Extract/Supply Fans + Noise Attenuation for Smoke Extract Fans + Conclusions

Single Shaft Smoke Control System Supply Extract Corridor Smoke Damper & Grille for exhaust Conclusions Smoke Extract Fans for exhaust Weathered AOV for supply air at head of staircase

+ + + + + Single Shaft Smoke Control System – additional requirements Corridor Temperature Sensor Variable Speed Drive for Extract/Supply Fans + + Standard AOV + Ceiling Grilles Fire Damper Between Stair & Corridor + + Conclusions Weathered AOV Noise Attenuation for Smoke Extract Fans

D-t-d damper above ceiling? Multiple shaft systems Smoke damper D-t-d damper above ceiling? With this system, additional day to day ventilation dampers above the ceiling are necessary – to balance the air flow (allowing multiple floors to be ventilated simultaneously) and to ventilate the ceiling void (therefore dealing with the majority of the heat load at source). Conclusions

More critical on ambient air systems: Control Options More critical on ambient air systems: Cyclical Control On activation, a limited number of floors (typically 3 to 4) will ventilate for a defined period, before shutting down and activating the next set of floors Limited benefit No balancing required Smaller airflow rates/lower noise High damper usage Low turnaround on taller buildings 2. Constant Control All floors can be ventilated simultaneously. Improved performance Balancing required Higher airflow rate will almost certainly need attenuation Higher energy consumption Conclusions

Details that count - Fans Environmental Control Requirements – Mechanical Shafts Details that count - Fans Dual purpose smoke extract fans can be used, but: High tip clearance means low efficiency – high energy bills Smoke fans are generally noisy Future energy use restrictions from Europe may prohibit dual purpose fans on the basis of efficiency limits. Consider smaller secondary fans?

Don’t expect CIBSE levels of accuracy (temperature or airflow) The solutions described up to now provide a nominal amount of ventilation using outside air only. They will improve conditions in the corridors relative to no ventilation, but they may not provide comfortable conditions. Manage expectations Don’t expect CIBSE levels of accuracy (temperature or airflow) Limited number of floors ventilated simultaneously Systems will alleviate stuffiness and limit overheating Corridors are transit spaces and don’t need close control (except in high value buildings with demanding residents) Conclusions

Colt CoolShaft Corridor Evaporative Cooling System So whilst a simple ventilation system based on supplying outside air alone will alleviate stuffiness and limit overheating, with the CoolShaft; we are able to reduce temperatures to below the outside ambient providing active cooling in the corridors. Conclusions

Colt Corridor Coolstream Colt’s CoolShaft Evaporative Cooling Ventilation System uses the cooling power of water to reduce the temperature, creating a more favourable environment in the corridors Running and maintenance costs are extremely low and the warmer the outside air, the more efficient evaporative cooling becomes. Conclusions

CoolShaft vs. basic outside air cooling With CoolShaft 35ºC Conclusions With Outside Air

CFD Case Study CFD model comparison to assess the expected temperatures within the corridors as a result of the given heat load. Using ambient air as at the method of ventilation Using CoolShaft Studies are carried out using FloVent CFD for a typical level within a building. The results shown represent a worst-case, steady-state condition. Conclusions

Heat Source Ceiling Grilles (x4) Extract Point Supply Point Conclusions

outside/ambient air 27.0ºC low-level 27.5ºC mid-level 28.0ºC high-level Coolshaft 21.7ºC low-level 21.8ºC mid-level 22.4ºC high-level Conclusions

Temperatures within corridors using outside/ambient air Avg. ceiling void temperature 38ºC Peak. ceiling void temperature 40ºC Conclusions

Coolshaft Avg. ceiling void temperature 30ºC Peak. ceiling void temperature 35ºC Conclusions

Low cost of operation and maintenance Colt CoolShaft Offer a reduction in energy costs of up to 90% compared to conventional air conditioning Low cost of operation and maintenance Free from refrigerants, no F gas compliance Integrated water quality system, simple technology VDI 6022 certification for water hygiene Filtered air supply (G4 & F7 filter options available) Conclusions

Next Step – Air conditioning Higher costs – both capital and operating Introducing refrigerant and management issues Space Better temperature control Conclusions

Questions?