Environmental house project Jack Bradley

What will be covered in this lecture? (1) Why people need a house (2) How technology provides a house (3) Design skills

How many types of house can you name?

Traditional Houses (1) Yurt (2) Igloo (3) Grass House (4) Pueblo

Traditional Houses (5) Tepee (6) Trullo (7) Forest Pavillion (8) Mandan lodge

Traditional Houses (9) Bedouin tent (10) English Cottage

Jack and Joanne have moved again!

Reasons for diversity Reasons For Diversity Materials Climate Ways of Life Technology Economics Socio – cultural factors

Why people need a house? (1) Physical comfort (2) Domestic activities (3) Socio – cultural factors

What does technology provide? (1) Materials (2) Services (3) Construction

Wood – Its properties (1) Resists tensile and compressive forces (2) Easy to work with simple tools (3) Light and easy to manipulate (4) Good thermal insulator (5) Spans distances (6) Feels warm

Influence of Services (1) Gas (2) Heating (3) Drainage (4) Electricity (5) Hot water (6) Cold water

Design Skills Required (1) Analysis (2) Synthesis (3) Evaluation

Keeping Warm (1) Location (2) Orientation (3) Shape

Orientation Wind/weather Sun – overheating V natural heat Topography – drainage, stream use, shelter Natural shading – trees – summer/winter (deciduous)

Green/Sustainable Building Definitions: To be classed as a green building it is “…essential for the environmental impact of all its constituent parts and design decisions to be evaluated.” “ A healthy built environment based on resource efficient and ecological principles.”

Design Principles Reduce energy in use Minimising external pollution and external damage Design in harmonious relationship with surrounds Avoid destruction of natural habitats Re-use rainwater Treat and recycle waste water Minimise extraction of materials Minimise waste materials provided (typically 10%)

Green design Solar Collector Rainwater Cistern Conservatory Earth heat storage bed Power generation (wind, water etc) Waste recycling system Insulation Renewable materials

Example Sketch a graph of temperature against time for a house where the heating pattern is as follows. The heating is turned on at 6am and off at 11am. It is turned on again at pm and off again at 11pm. When the heating is on, the occupants require the temperature to be 23C. On your graph, indicate the approximate values of the average inside temperature.

Heating a house Heat Flow Rate = U-Value * Area temperature difference Ventilation loss = Specific heat capacity * Mass flow rate of air * Temperature difference Mass flow rate of air = Air change rate * House Volume * density of air 3600

Equation Ventilation Loss = 0.33 x House Volume x Air change rate x Temperature difference. Average temperature and degree-days Total heat required = Specific loss * degree days * 86400

Example 2 Calculate the rate of heat loss from the house shown below when the temperature difference between the inside and the outside is 20C. The house has an air change rate of 1.0ach, walls with U-values of 0.6Wm-² C-1 and U-values of 0.3Wm-² C-1 for the roof, 0.8 for the floor, 3.4 for doors and 5.6 for the windows. The total area of window is 12m² and there is 4m² of external doors 6m 5.5m

Solution 2 Total wall area = 4 x 5.5m x 6m =132m² Net wall area = total wall area – window area – door area =132m² - 12m² - 4m² =116m² Floor area = 6m x 6m = 36m² Roof area = 6m x 6m = 36m² House volume = 5.5m x 6m x 6m = 198m² Fabric loss = U-Value x area x temp. difference For walls: fabric loss = 0.6 x 116 x 20W = 1392W For the floor: fabric loss = 0.8 x 36 x 20W = 576W For the roof: fabric loss = 0.3 x 36 x 20W = 216W For the windows: fabric loss = 5.6 x 12 x 20W = 1344W For the doors: fabric loss = 3.4 x 4 x 20W = 272W

Total fabric loss = 1392W + 576W + 216W W + 272W = 3800W Ventilation loss = 0.33 x house volume x air change rate x temp. difference = 0.33 x 198 x 1 x 20W = W Total rate of heat loss = fabric loss + ventilation loss = 3800W W = W Specific loss = total rate of heat loss temperature difference = W 20 C

Internal and Solar gains In a typical house, the total gains from all sources will be about 1000W. Te specific loss will approximate to 255W C^-1 Temperature rise from internal & solar gains = Total gains / Specific loss

RegionDegree DaysRegionDegree Days Home Countries2137Northumberland2727 Southeast2445North Yorkshire2534 South2286South Yorkshire2398 Southwest1966East Anglia2468 Severn Valley2235West Scotland2615 West Midlands2527East Scotland2744 Merseyside2389North Scotland2903 Cumbria2556Wales2276

Building activity relationship charts