Lesson -1: Principles of Eco-Design(Part Four)

4.Thermal zonning

                               -a thermal zone represents an enclosed space in wich the air is free to flow arround and whose thermal conditions are relatively consistent,in most cases any roomed closed with a door would be a separated zone but sometimes temperatures in different of large spaces can vary ,in wich cases the space can be divided into a number of small zones with adjoining elements defined as voids,in this way heat is free to flow among the zones but their thermal caracteristic can be analyzed individually.

                             -we like different temperatures in different rooms- we like bathrooms to be very warm, living rooms to be a comfortable cosy temperature, and bedrooms to be cooler, an efficient eco-design  recognises these differences and creates different thermal zones for the different rooms,some approximate figures for living temperatures are as follows:

Hot zone	20-23°	Bathrooms, airing cupboards, rooms for drying clothes, kitchen
Warm zone	18-21°	Living rooms, study, children's bedrooms
Cool zone	16-18°	Adult bedrooms
Cold zone	under 16°	Rooms that are not in use, storage rooms, garage, basement

                          -there are very great energy savings to be made from cutting just a couple of degrees off these temperatures, we live at the low end of these ranges and find that the maximum temperature we need is 19 degrees.

                          -thermal zoning tries to ensure the best match possible between the distribution of rooms and the distribution of the available heat, the ideal thermal zoning is:

• hot zone -the ideal place for hot rooms is in the very centre of the house, with no external walls so that the heat can radiate out into the rest of the house, the next best option is with a South facing window (which may be better for a bathroom where natural lighting and good ventilation is desireable.

• warm zone -the main living rooms need constant warmth and light and are best placed on the South side of the house with large windows and good thermal capacity to hold any thermal gain through the evening. Kitchens can generate a great deal of heat, the ideal location for a kitchen is therefore facing into the centre of the house, with the cooker placed on an internal wall.

• cool zone -adults tend to make little use of bedrooms except for sleeping and do not need to be especially warm, in a well insulated house a large part of their heating can be supplied by warmth rising from a well heated room below, adult bedrooms can be placed on the cooler side of the house,however, they need good light and an easterly window or skylight is preferred.

• cold zone -little used rooms are best located along the colder and darker North side of the house, rooms that need to be heated occasionally, such as a spare bedroom, perform better with a low thermal capacity with insulation on the inside of the room, storage rooms need to be kept dry but heat, light, and thermal capacity are of little concern, though the preference is for constant cool temperatures, basements and rooms under the stairs, if dry, are perfect for storage, durable items can be stored outside the insulated envelope altogether- such as under the eaves or in unheated sheds, in both cases the main concern is keeping them dry.