Fan Convector Heating - Smiths Environmental Products

Company Overview

Smith’s environmental products limited was formed in 1991 and has grown to become the leading supplier of domestic and light commercial fan assisted hydronic heat emitters. The complete product range is manufactured in house in a specialist facility in the UK and is the UKs market leader, with significant shares of both the North American and European markets. Smith’s environmental fan coils limited is a subsidiary of Smiths environmental products limited. It offers a range of water side fan coil products incorporating the latest technology with high performance at low noise levels. In addition to our standard product range we offer both the design expertise and manufacturing flexibility to meet any special modification or bespoke design. We work alongside all the leading controls companies enabling you to be confident that your choice of controls will function perfectly alongside our fan coil range.

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Operating from 40,000 square feet of factory and office space near Chelmsford in Essex, we manufacture our product range from the raw material through to the finished product utilising computerise design and automated production techniques. At Smith’s we recognise that quality is about more than just the product, it's an approach that runs throughout the business and is centred on meeting and exceeding customers’ expectations. Processes are constantly monitored and evaluated with a focus on continuous improvement. Manufacturing facilities are regularly appraised and meet with exacting standards of national approval boards, such as UL, CSA and KEMA, we're also an iso 9001 approved company, another example of our commitments to effective working processes and management systems. We are thoroughly committed to recycling and waste management or process is incorporate waste minimalization procedures, ensuring minimal waste and maximum recycling. All our products are designed with energy efficient performance in mind, particularly our latest product, the eco vector intended to work from both existing and renewable energy sources. All product packaging is fully recyclable, offering further testament to our commitment to the environment.

Introduction

This CPD will be discussing the benefits of fan convectors in relation to sustainability, efficiency, suitability for various environments, and integration with existing systems.  The CPD is structured into four parts: 

• principles of forced convection heaters,
• benefits for sustainability,
• standards and regulations,
• and applications.

Principles of Forced Convection Heaters

This CPD it is not necessary for us to delve deeply into the theory of heat transfer. It is however worth looking at basic principles and the three broad categories in which heat transfer are grouped. They are conduction (the transfer of heat through a solid material), radiation (the transfer of heat in the form of electromagnetic waves) and, convection (the transfer of heat by moving air). 

Conduction

Conduction is the transfer of heat through a solid material, as heat is conducted through a material, it can transfer its energy into an adjoining space, an example of this might be under floor heating where hot pipes or cables conduct heat through the floor material into the room above.

Radiation

Radiation is the transfer of heat in the form of electromagnetic waves. Radiant heat does not rely on transfer by air, an example of this is, the sun's heat which we receive and is transfer to us through the vacuum of space. Radiators and electric bar heaters and, open fires also radiate heat.

Convection

Convection is the transfer of heat by moving air. As hot air rises from a heat source the air cools and then falls again, causing natural convection currents. In reality heat transfer often works through a combination of these three methods.

Most homes and many office commercial and civic buildings in the UK are typically heated by radiator panels. Radiators of course radiate heat but they also use the natural convection process. Part of the problem with natural convection radiators is that warm air rises quickly and very close to the heat source. It then cools and falls, and the process is repeated, this means the warmest areas in a room are close to and immediately above the radiator. With a forced or fan convectors process warm air is directed into the room quickly at a lower level. It then rises as warm air cools and repeats as before.

The difference with fan convectors is that warm air is distributed over a greater area giving a greater comfort level over the entire room rather than in isolated hotspots. Warm air is distributed where it is needed for example to the room user before it calls at a higher level.

Just like a standard radiator panel fan convectors are hydronic which means they require connection to a wet central heating system; they also require an electrical connection to run a small fan. Hot water from the central heating system passes through the heat exchanger transferring its heat to the aluminium fins, cooler air is drawn in by the fan and heated as it passes over the heat exchanger. Before being expelled gently back into the room this gives a more even temperature and will heat a room in much less time than a traditional panel radiator.The fan does not come into operation until the water passing through the heat exchanger reaches 40°C, or an alternative temperature set by the installer. This ensures that cooler air is not circulated at start-up and allows the unit to switch on and off automatically in conjunction with the central heating system.

Because fan convectors are so good at distributing heat where and when it is needed, they have many more advantages over conventional panel radiators: 

• They require less energy to heat the same size space they heat space quicker than natural convectors.
• They are compatible with standard central heating systems.
• They work at lower temperatures making their surface temperatures far lower than panel radiators, and therefore ideal for children and the elderly,
• They are compact designed to be installed in those dead spaces freeing up valuable space and ensuring that the room is not designed around the heating.

Benefits for Sustainability

In independent tests carried out by BSRIA fan convectors were shown to use 24% less energy in heating of a room when installed as part of a boiler driven central heating system. This percentage included the energy used to run the small fan inside the unit. Because energy uses lower running costs are lower, fan convectors use very small amounts of electricity to run the fan. Based on actual usage of 1300 hours with an output of 21 wants and charged at 0.1 pence per kwh electricity costs would be less than £5 per year. Furthermore, when connected to a low temperature system such as those using ground or air source heat pumps, the energy saving increased to 31%.

Sustainability and energy efficiency are ever more important when choosing heating systems for both new build and refurbishment projects. Today renewable technologies such as ground and air source heat pumps and solar panels are easily available and a more viable option. Since the introduction of central heating systems, we have become familiar with large steel panel radiators in every room, unlike fan convector technology, they require large volumes of very hot water to perform to maximum efficiency. This means they are much less efficient in the modern heating systems of today as water temperatures are much lower. Fan convectors use 5% of the water volume of an equivalent output radiator, meaning faster heat up times and are quicker responding to changing weather conditions.

Heat pumps are incredibly efficient especially when combined with under floor heating part of the reason for that efficiency comes from the low temperature differential between heat source and heat emitter. As a rule of thumb for every 1°C increase in flow temperature, a heat pump reduces its efficiency by 2.5%.

Even on a standard boiler based system a fan convector allows you to run the system at lower temperatures, ensuring your boiler can be in condensing mode where it achieves higher efficiency levels and reduced costs.

Standards and Regulations

Fan convectors are regulated by the same standards and regulations as other conventional heating systems, including radiators and electrical heaters. Part l of the approved documents gives guidance on commissioning and providing specific user information. The domestic and non-domestic building services compliance guides give detailed guidance for persons installing fixed building services in new and existing buildings. All plumbing and electrical work should be completed to current legislation and best practice. Like all heat emitters, fan convectors must provide provision for individual room temperature control, many fan convectors have integral thermostats.

Standard Assessment Procedure (SAP)

The Standard Assessment Procedure (SAP) is adopted by government as the UK methodology for calculating the energy performance of dwellings. Currently sap defines forced convection heaters as fan coil units, fan converters. When comparing a heat pump system with conventional emitters the results are favourable for forced convection heaters.

Fan convectors show a 7.5% increase in sap rating, in comparison to standard radiators and only a 2.5% reduction against under floor heating. It's also worth noting that certain types of under floor heating suffer here because they have low responsiveness and therefore need to be used for longer periods to get a room up to temperature.

When compared to both these under floor systems and radiators, forced convection heaters have extremely fast response times. In addition, it is impractical to install under floor heating into existing houses and the upstairs of new houses.

Applications

Because fan convectors are so versatile there is a heating solution for every type of space in both home and workplace.

Summary

In summary we have seen the principles behind forced convection heaters, they are compact, quicker to heat- even when compared to under floor heating, compatible with standard central heating systems and, work at lower temperatures. We have seen their sustainability benefits such as, 24% less energy used for boiler systems and 31% less energy on ground and air source heat pumps, and we have seen their beneficial advantages over radiator efficiency for sap calculation, and advantages over under floor heating systems for refurbishment and certain building types.

We have seen how they can be integrated with existing hot water heating systems with the same skills and standards used by conventional heating systems, and seen their suitability and versatility for use around the home and in the workplace.

Thank you for listening.