Energy efficient ventilation solutions Paul Compton

I J O’Hea, Colt Founder A private company founded in 1931 I J O’Hea OBE ( ) 2013 Group turnover £152 million Manufactures in the Brazil, China, the Netherlands, Saudi Arabia, the UK and the USA A brief history of Colt

Current UK Business markets Smoke Control Solar Shading Natural Ventilation Louvre Environmental Comfort Control

Programme Introduction Natural ventilation Mechanical ventilation Cooling PIATRA

INTRODUCTION Environmental Control Requirements – Natural AOV What’s important to you? First cost Running cost Total cost of ownership / life cycle costing Carbon (total or embodied) Energy (total or embodied)

Environmental Control Requirements – Natural Shafts Embodied energy and carbon Accurate information is very difficult to get Manufacturers haven’t grasped the nettle For most systems it’s outweighed by energy in use Aluminium 1tCO 2 /t recycled, 3-20tCO 2 /t raw INTRODUCTION

Environmental Control Requirements – Natural Shafts First cost Mechanical ventilation – low cost = high energy and carbon in use? Natural ventilation – low cost = low energy and carbon? Our industry makes first cost so important - specifications are critical Approved document L and the associated building services guides? INTRODUCTION

Environmental Control Requirements – Natural Shafts Running cost and total cost of ownership Important to the occupier but not necessarily to the builder Soft Landings can help by at least getting the systems set up properly, but if the design is inherently inefficient ……... Reduce loads by solar control, tight building, low energy lighting, limiting plug loads, etc INTRODUCTION

Environmental Control Requirements – Natural Shafts - If you really want low energy and carbon Generally simple, lightweight systems, therefore with low embodied energy and carbon Virtually no energy use in operation But in heated buildings there will be extra winter energy use to counteract the extra fabric and ventilation heat losses – these can be significant NATURAL VENTILATION

Environmental Control Requirements – Natural Shafts So why are all buildings not naturally ventilated? Conditioning of the incoming air is generally not possible Close control of internal conditions is generally not possible Noise control can be difficult Building form may not suit natural ventilation Controls need to be well thought through and designed Lack of experience/confidence NATURAL VENTILATION

Environmental Control Requirements – Natural Shafts Energy and carbon Take a simple example of a heated and naturally ventilated DIY store requiring roof ventilators with 40m 2 aerodynamic area Consider 2 options: Colt Seefire or Colt Firelight NATURAL VENTILATION SeefireFirelight U value Leakage (m 3 /h/m 2 at 50Pa 1707 Installed cost£19 000£30 500

NATURAL VENTILATION

Environmental Control Requirements – Natural Shafts The embodied energy and carbon of a fan are probably similar to those of an equivalent natural ventilator but we also have: ducting, controls, wiring, etc Running costs: every kWh typically costs 10p. At an SFP of 1.5 that’s 15p per hour per m 3 /s air flow – and there are 8760 hours per year With a typical UK power generation mix that equates to 670 kgCO 2 and £150 per m 3 /s per 1000 hours running time. MECHANICAL VENTILATION

Environmental Control Requirements – Natural Shafts How can we minimise energy use? Don’t over estimate the required flow rate Limit usage by mixed mode ventilation Reconsider duct sizing Make ducts as low resistance as possible – simple layouts, minimum bends, tuning vanes or radiused bends, etc and minimise duct leakage Choose efficient fans Use VSD control if practical Consider EC motors for smaller fans MECHANICAL VENTILATION

Environmental Control Requirements – Natural Shafts Energy and carbon Take the previous example Consider the option of using mechanical extract instead 55 m 3 /s extract at 0.5 SFP (roof units) Initial cost £24000 Running 1000 hours p.a. (summer daytime) £2750 p.a. electrical cost, 4500 kgCO 2 Winter heat losses £1300 p.a., kgCO 2 Overall “good” natural ventilation system gives 2 year payback “good” natural ventilation system reduces CO 2 emissions by 9500 kg p.a. MECHANICAL VENTILATION

Environmental Control Requirements – Natural Shafts Energy and carbon Three options: refrigerant, adsorptive, adiabatic Very different performance and total cost of ownership Refrigerant cooling has a high cost but is well established and provides excellent control of conditions Adiabatic provides virtually free cooling, but has limitations COOLING

Environmental Control Requirements – Natural Shafts Adiabatic cooling Operates by evaporation of water, converting sensible heat to latent heat and thus reducing the dry bulb air temperature Only operating cost/energy is fan and water pump power. No refrigerants. Ideal for providing cooling under peak conditions when simple mechanical ventilation is insufficient Limitations: System LAT floats with incoming air temperature and humidity Cannot dehumidify Increases humidity, needs a high percentage FAI COOLING

Environmental Control Requirements – Natural Shafts Comparison of carbon and ownership costs A proprietary Colt program (not available for external use) Uses Meteonorm local hourly weather data Designed to compare systems, not to give accurate running cost forecasts Allows comparison of more than just first cost for Colt systems Used to provide the comparisons in this presentation PIATRA

Design Commissioning MaintenanceEquipment/Controls Installation The End