Energy resources Fossil fuels Coal
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Energy resources Fossil fuels Coal Oil Gas Nuclear energy Coal 22% Gas 24% Nuclear 7% Petroleum 39% Image by MIT OCW. Energy resources Renewable energies Wind Coal 22% Gas 24% Nuclear 7% Petroleum 39% Renewables 8% Image by MIT OCW. Energy resources Renewable energies Wind E TUD Solar thermal -15o o LATI LATITUDE + 15 LATITUDE 1 2 3 Image by MIT OCW. Coal 22% Gas 24% Nuclear 7% Petroleum 39% Renewables 8% Image by MIT OCW. Energy resources Renewable energies Wind Solar thermal Photovoltaic Coal 22% Gas 24% Nuclear 7% Petroleum 39% Renewables 8% Image by MIT OCW. Energy resources Renewable energies Æ Wind Solar thermal Photovoltaic Hydroelectric (& Tidal) Coal 22% Gas 24% Nuclear 7% Petroleum 39% Renewables 8% Image by MIT OCW. storage issue Energy resources Energy conversion Æ Electricity Electric heating only half as efficient as direct fuel combustion Conversion Electrical Energy Chemical-to-heat Steam Turbine Boiler Heat-to-mechanical Generator Fuel Chemical-to-mechanical Condensate Pump Condensor Waterway Cool water in Warm water out Image by MIT OCW. Electrical Efficiency, η Device Open fireplace 0.30 Coal fired boiler, manual feed 0.60 Coal fired boiler, automatic 0.70 Oil fired boiler 0.70 Gas fired boiler 0.75 Steam piston engines 0.05-0.20 Steam turbines 0.18-0.40 Petrol engines 0.20-0.28 Diesel engines 0.32-0.38 Gas turbines 0.30-0.35 AC generator 0.97 AC motor 0.92 Transformer 0.98 Lead-acid battery (input-output) 0.75 Electric heating 0.99 Image by MIT OCW. Active controls: HVAC Two parameters to be known capacity ­ depends on building’s heat losses ­ depends on ΔT between comfort °T and worst outside °T heating requirements ­ depends on time of the year Active controls: HVAC Local heating Oil heater Stove (solid fuel) Gas heater Electric heater Type Infrared lamps Heat emission (%) Radiant 100 Incandescent radiators 80 20 Medium temperature (tube or panel) radiators 60 40 Low temperature panels (oil filled) 40 60 Convectors 20 80 100 Fan-convectors Image by MIT OCW. Convective Storage (block) heaters 10 90 Floor warming 20 80 Ceiling warming 70 30 Active controls: HVAC Local heating (Warm) Sink (room) temperature (oC) 20 30 40 50 20 Oil heater 15 COP Stove (solid fuel) 10 Gas heater 5 Electric heater 0 -10 0 10 20 30 (Cold) Source temperature (oC) ­ Heat pump Image by MIT OCW. Low pressure liquid High pressure liquid Condenser Evaporator Choke (Pressure release valve) Sink Image by MIT OCW. Source High pressure vapour Compressor Low pressure vapour Active controls: HVAC Water pipe Central heating for 1161 1161kWh/m kWh/m33KK Air based Water based Air duct for for 0,33 kWh/m 3K Return duct Supply ducts Images by MIT OCW. Burneroil tank Oil Tank Fan Dust filter Control valve Convector Air vent Return fitting Pump Boiler Compression tank Active controls: HVAC Ventilation and air-conditioning Mechanical ventilation Air-conditioning ­ Conventional room conditioner ­ Open-cycle cooling Radiating surfaces Room air Fibrous material pad e.g. wood shavings in cheese cloth Perforated drip pipe Outdoor air C M E CD Pump Motor Fan Images by MIT OCW. Sump with float valve for make-up water Active controls: HVAC Integration and occupants’ comfort Floor warming slow but comfortable Convectors quick but not for massive/badly insulated spaces Local radiative heating towards people for large spaces Passive and active heating combination Heating system coherent with solar gains stops when gains overcome needs requires temperature or solar radiation sensor (separation N/S) S N SAF AF AF VF VM VF VM Image by MIT OCW. Passive and active heating combination Heating system coherent with solar gains stops when gains overcome needs requires temperature or solar radiation sensor (separation N/S) requires low inertia of heating system Radiator Air [h] 0 2 4 6 8 10 12 14 [h] 16 0 2 4 6 8 10 12 14 16 Floor [h] 0 2 4 6 8 10 12 14 16 Image by MIT OCW. Passive and active heating combination Heating system coherent with solar gains stops when gains overcome needs requires temperature or solar radiation sensor (separation N/S) requires low inertia of heating system autoregulation difficult with high temperature heating systems Active Heating and Cooling Reading assignment from Textbook: “Introduction to Architectural Science” by Szokolay: § 1.6 + § 4.1 - 4.2 Additional readings relevant to lecture topics: "How Buildings Work" by Allen: pp. 77 - 88 in Chap 10 + Chap 15 "Heating Cooling Lighting" by Lechner: Chaps 2 + 8 + 16 “The Technology of Ecological Building“ by Daniels: Chaps 10 – 12 More detailed information about renewable energy "Sustainability at the cutting edge – Emerging technologies for low energy buildings" by Smith
