Energy resources Fossil fuels ƒ Coal ƒ Oil ƒ Gas ƒ Nuclear energy

Coal 22% Gas 24% Nuclear 7%

Petroleum 39%

Image by MIT OCW. Energy resources

Renewable energies ƒ Wind

Coal 22% Gas 24% Nuclear 7% Renewables 8% Petroleum 39%

Image by MIT OCW. Energy resources

Renewable energies ƒ Wind o -15 LATIT o LATITUDE LATITUDE + 15 ƒ Solar thermal UDE

1 2 3

Image by MIT OCW.

Coal 22% Gas 24% Nuclear 7% Renewables 8% Petroleum 39%

Image by MIT OCW. Energy resources

Renewable energies ƒ Wind ƒ Solar thermal ƒ Photovoltaic

Coal 22% Gas 24% Nuclear 7% Renewables 8% Petroleum 39%

Image by MIT OCW. Energy resources

Renewable energies Æ storage issue ƒ Wind ƒ Solar thermal ƒ Photovoltaic ƒ Hydroelectric (& Tidal)

Coal 22% Gas 24% Nuclear 7% Renewables 8% Petroleum 39%

Image by MIT OCW. Energy resources

Energy conversion Æ Electricity ƒ Electric heating only half as efficient as direct fuel combustion

Conversion Device Efficiency, η

Open fireplace 0.30 Coal fired boiler, manual feed 0.60 Electrical Energy Chemical-to-heat Coal fired boiler, automatic 0.70 Oil fired boiler 0.70 Steam Boiler Turbine Gas fired boiler 0.75 Steam piston engines 0.05-0.20 Heat-to-mechanical Steam turbines 0.18-0.40 Generator Petrol engines 0.20-0.28 Fuel Chemical-to-mechanical Diesel engines 0.32-0.38 Condensate Gas turbines 0.30-0.35 Pump AC generator 0.97 Condensor AC motor 0.92 Transformer 0.98 Electrical Waterway Lead-acid battery 0.75 (input-output) Cool Warm water in water out Electric heating 0.99

Image by MIT OCW. Image by MIT OCW. Active controls: HVAC

Two parameters to be known ƒ capacity ­ depends on building’s heat losses ­ depends on ΔT between comfort °T and worst outside °T ƒ heating requirements ­ depends on time of the year Active controls: HVAC

Local heating ƒ Oil heater ƒ Stove (solid fuel)

Heat emission (%) ƒ Gas heater Type Radiant Convective ƒ Electric heater Infrared lamps 100

Incandescent radiators 80 20

Medium temperature (tube or panel) radiators 60 40

Low temperature panels (oil filled) 40 60 Convectors 20 80 Fan-convectors 100 Storage (block) heaters 10 90 Floor warming 20 80 Ceiling warming 70 30 Image by MIT OCW. Active controls: HVAC

(Warm) Sink (room) temperature (oC) 20 Local heating 30 40 20 50 ƒ Oil heater 15 P

ƒ Stove (solid fuel) O 10 C

ƒ Gas heater 5

0 ƒ Electric heater -10 0 10 20 30 (Cold) Source temperature (oC) ­ Heat pump Image by MIT OCW.

High pressure liquid Low pressure liquid Choke (Pressure release valve) Condenser Evaporator

Sink Source

High pressure Low pressure Image by MIT OCW. vapour Compressor vapour Active controls: HVAC Water pipe Central heating for 11611161 kWh/m kWh/m33KK ƒ Air based

ƒ Water based Air duct for for 0,33 kWh/m 3K

Control valve Supply Convector ducts Air vent

Compression Burneroil Return fitting tank tankOil Pump

Return duct Tank Fan Boiler Dust filter

Images by MIT OCW. Active controls: HVAC Ventilation and air-conditioning ƒ Mechanical ventilation ƒ Air-conditioning ­ Conventional room conditioner ­ Open-cycle cooling ƒ Radiating surfaces

Fibrous material pad e.g. wood shavings Room air in cheese cloth Perforated drip pipe

CM E Outdoor air CD

Pump Motor Fan

Sump with float valve for make-up water Images by MIT OCW. Active controls: HVAC

Integration and occupants’ comfort ƒ Floor warming slow but comfortable ƒ Convectors quick but not for massive/badly insulated spaces ƒ Local radiative heating towards people for large spaces Passive and active heating combination Heating system coherent with solar gains ƒ stops when gains overcome needs ƒ requires temperature or solar radiation sensor (separation N/S)

S N

SAF AF

AF

VF VF

VM VM

Image by MIT OCW. Passive and active heating combination Heating system coherent with solar gains ƒ stops when gains overcome needs ƒ requires temperature or solar radiation sensor (separation N/S) ƒ requires low inertia of heating system

Air Radiator

[h] [h]

0 2 4 6 8 10 12 14 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 ƒ stops when gains overcome needs ƒ requires temperature or solar radiation sensor (separation N/S) ƒ requires low inertia of heating system ƒ autoregulation difficult with high temperature heating systems Active Heating and Cooling

Reading assignment from Textbook: ƒ “Introduction to Architectural Science” by Szokolay: § 1.6 + § 4.1 - 4.2 Additional readings relevant to lecture topics: ƒ "How Buildings Work" by Allen: pp. 77 - 88 in Chap 10 + Chap 15 ƒ "Heating Cooling Lighting" by Lechner: Chaps 2 + 8 + 16 ƒ “The Technology of Ecological Building“ by Daniels: Chaps 10 – 12 More detailed information about renewable energy ƒ "Sustainability at the cutting edge – Emerging technologies for low energy buildings" by Smith