Reducing Heat Transfer

In the previous section, the three types of heat transfer were discussed:-

1. Conduction - Heat moving through a solid, by causing particles to vibrate more.

2. Convection - Heat moving through a liquid moving in a convection current.

3. Radiation - Heat moving as Electromagnetic radiation (Infra-Red radiation).

Heat transfer is a very useful process, it allows us heat our food and homes, to find missing people or to heal injuries, but it is not always a good thing.

In lots of situations, heat transfer is not wanted, or in fact could be dangerous. For example, if you lose enough heat from your body, you can die through Hypothermia. This means that we need ways to reduce heat moving. Stopping heat moving is not possible, but we can slow down the process.

We can not stop heat escaping an object, but we can reduce it. Each type of heat transfer can be reduced using different materials. These can be used to save money on heating in the home, or to even save your life!

Insulation in the Home

There are many different ways to reduce heat loss from the home. before we can decide which are best, we must first understand where heat is lost from the home. The diagram below shows where heat can be lost from the home:-

As can be seen, there are many different ways to lose heat from the home. Each method below will reduce heat loss by blocking one or more heat transfer processes.

As a Building Surveyor, you would advise people who own or want to buy a building whether it meets building regulations or needs any serious repairs.

Your clients could be home owners or large commercial and industrial companies.

You’d advise them about the design and construction of new buildings. You’d inspect existing buildings and explain what maintenance and repairs they need. You would have to be able to understand your client’s business needs.

You’d focus on three main areas: surveying, legal work, and planning and inspection.

Depending on the size of the company, you may cover all of these tasks or you might specialise in just one. Language skills may be useful if you want to work overseas or for a company with international clients.

Double Glazing

As can be seen above, 25% of heat energy is lost through windows and doors. A good way to reduce heat being lost through windows is to replace single glazing with double glazing.

The diagram below shows a cut-through of a double glazing window:-

As can be seen in the diagram above, a double glazed window is made of two panes of glass, separated by a gas filled gap. As gases are poor conductors of heat Energy, the trapped gas reduces the heat Energy lost through conduction.

Cavity Walls

As can be seen above, 35% of heat Energy is lost through walls. A good way to reduce heat being lost through walls is to replace single walls with a cavity wall.

The diagram below shows a cut-through of a regular wall and a cavity wall:-

A cavity wall works in the exactly the same way as double glazing. A cavity wall is a wall made of two walls, separated by a gas filled gap. As gases are poor conductors of heat Energy, the trapped gas reduces the heat energy lost through conduction. The heat lost through the wall can be reduced even more by filling the air gap with insulating foam, as shown in the diagram below:-

Loft Insulation

As can be seen above, 25% of heat Energy is lost through the roof. A good way to reduce heat being lost through the roof is to use loft insulation.

The diagram below shows how loft insulation reduces heat loss:-

As can be seen in the diagram above, loft insulation uses a layer of insulating material such as fiberglass to prevent warm air rising through the ceilings of the rooms below. This insulation therefore reduces the heat Energy lost through convection. Some fibreglass will also by coated on the underside with reflective material to reduce the heat Energy lost through radiation.

Floor Insulation

As can be seen above, 15% of heat Energy is lost through the floor. A good way to reduce heat being lost through the floor is to use an insulating layer of material such as carpet with underlay.

The diagram below shows how floor insulation reduces heat loss:-

As can be seen in the diagram above, floor insulation works by placing a thick layer of carpet with underlay on the floor. Floor insulation helps reduce the heat Energy lost through conduction.

The table below summarises the methods of insulating a home to reduce heat loss:-

As a Thermal Insulation Engineer, you would fit insulation around pipes, boilers and ductwork to help them retain heat. You might carry out jobs in factories, offices, power stations or on ships.

You may also work on the removal of old materials such as asbestos. This substance is dangerous. Your job would involve other risks as well, such as working at heights, so it would be very important to follow health and safety rules carefully.