Thursday, 9 May 2013

Community Heating Systems

What is a Community Heating System?

A community heating system is where a single heat source supplies heat to a number of different properties. Examples include a system that heats a block of flats or a large scale heating system that supplies multiple buildings. Such systems work best in densely built areas with large numbers of dwellings in close proximity to one another; to ensure the system is efficient.

Systems across the world show a large range of different heating sources. Many use a typical boiler set up although new builds and refurbishments are often using renewable energy sources such as biogas or woodchip. Electric heating is particularly common with community heating systems due to their niche of heating densely built areas; a gas explosion could be devastating. Some community heating systems make use of solar and geothermal energy.

Here in the UK, some cities have adopted major community heating systems that heat whole districts.  In Nottingham for example, a community heating system heats 4,600 homes and a wide range of businesses.

How is the heat distributed?

Smaller community heating systems are similar to large scale central heating systems; making use of pumps, valves and insulated pipes.

The larger schemes use what are known as heat mains. Heat mains are series of pipes that are buried in the ground similar to other mains services and have stellar insulation to reduce energy loss and ensure optimum efficiency. A key feature of heat mains is that they can pump at different speeds, to adapt to what is required and keep costs at a minimum.

What differences will consumers see?

Consumers will still have radiators, thermostats, time switches/programmers and TRVs. The main difference is that instead of a boiler they have a Hydraulic Interface Unit which connects their home to the heat mains. This unit contains control valves and metering.

Thursday, 2 May 2013

How to Choose a Stove with a Built-In Boiler

If you're looking for a stove with a built-in boiler, otherwise known as a cooker with an integral boiler, then there are some key specifications you need to know before you choose which one to buy. All appliances that are gas-fired are potentially dangerous and if mistakes are made possible results include explosions, gas poisoning or hefty legal bills.

It should come as no surprise then that there are Government regulations associated with the specifications of these appliances that must be followed.

The appliance must have two independently controlled burners

  • Both the cooker and the boiler parts of the device must have separate burners.
  • A gas burner is simply a device that burns the gas fed into the appliance, and uses the resulting flame to heat products, such as the water in the boiler, and food in the cooker.

The boiler must have a Seasonal Efficiency (SEDBUK) value at 75% or higher

  • SEDBUK was developed in a Government programme to accurately display boiler energy performance and allow comparisons between manufacturers of boilers.
  • SEDBUCK % scores are split into various bands.
  • You'll need to make sure that the boiler you're installing is upper band E (74%-78%) or higher to meet legal requirements for a stove with a built-in boiler.

Pipework should be insulated according to the regulations for gas-fired central heating system pipes

  • The primary circulation pipes for circulation of hot water & heating must be insulated whenever they pass outside of a heated living space or through voids (such as within walls) with are ventilated from unheated areas.
  • This insulation should extend as far as possible along their length, only excepting areas where structural or joist penetration renders this impossible ( a joist is a horizontal support member running between walls and beams).
  • If a secondary circulation system will be used, all pipes kept hot within this system must be insulated.
  • If the new appliance is replacing an old one, all newly exposed pipes must be insulated according to the above mentioned procedure.

The minimum provisions for gas-fired central heating must satisfy the regulations regarding integral central heating boilers

  • Further details will be covered in a separate blog post.

Boiler interlock, zoning, time control, temperature control, hot water circuits must meet minimum provisions

  • Further details can be found in this blog post about what these provisions are.
  • However, with this type of boiler/stove setup there is an alternative solution: you can use a boiler management system that includes zoning, timing and temperature provisions that meet the above provisions.
  • If you replace an existing boiler with the new appliance you will need to make sure the rest of your setup meets the regulations. However, if your current set-up is below standards and you're just upgrading a component such as a thermostat, then you will not need to upgrade the rest (although leaving your system below standard is inadvisable).