Voltimum introduces heating and ventilating – and the new Voltimum UK HVAC Expert Panel

Indoor environments can contain a complex mixture of gaseous and particulate contaminants that building occupants and homeowners may be exposed to. These include water vapour, as well as emissions from cleaning products, construction activities, carpets and other furnishings, perfumes, cigarette smoke, electronic machines, water-damaged building materials, microbial growth (fungal/mould and bacterial), insects and external pollutants. Indoor temperatures, relative humidity and ventilation levels can also have an effect.

Therefore, indoor air quality (IAQ) - combined with energy saving and emissions reducing activities - has become an increasingly important health and safety issue. Energy saving measures have led to modern airtight buildings that can easily create IAQ problems, which result from the following causes:

• Indoor environment - temperature that is too low, excessive humidity and noise, plus certain lighting issues.
• Indoor air contaminants - chemicals, dusts, moulds or fungi, bacteria, gases/vapours and unpleasant smells.
• Outdoor environment - Radon gas.
• Insufficient outdoor air intake.

To counter these unwanted exposures and to improve the comfort, well-being and health of building occupants, ventilation is used. This is the process of replacing air in any space (bathroom, kitchen, shower room, the whole house, offices, retail spaces etc) to provide high indoor air quality. At work, it has also been proven to boost people's productivity. Good ventilation can also save money by reducing building maintenance requirements through getting rid of damp and the resulting moulds.

Ventilation techniques achieve these benefits by controlling the indoor temperature and replenishing oxygen, while removing unpleasant smells, smoke, dusts, airborne bacteria and carbon dioxide (CO2). Interior building air is kept circulating (in the spaces where ventilation is fitted), and this helps reduce air stagnation.

Heating, whether using stand-alone heaters or central heating, is also used to make life more comfortable for building occupants in cold weather. It too (used correctly) can improve productivity at work.

A central heating system provides warmth to the whole interior of a building, or part of that building, from one point to a number of rooms. Combined with other systems to control the building climate, the whole may become a heating, ventilating and air-conditioning (HVAC) system.

However, both heating and cooling systems use energy, so a major drive is towards making such systems as energy efficient as possible, as required by regulations, such as Parts L and F of the Building Regulations. The result has been the rapid development of far more energy efficient heating and ventilating products and systems, using new technologies and clever control strategies, as well as alternative systems, such as heat pumps.

A new Electrical Heating, Ventilation & Control Expert Panel:

Reflecting the growing importance of excellence in heating and ventilation, Voltimum UK and its partners involved in these two related sectors have just formed the 'Electrical Heating, Ventilation & Control Expert Panel'. Its members will meet regularly, with the aim of bringing smart home and building automation issues and opportunities to both manufacturers and to Voltimum UK users.

The Panel's aims include furthering adoption of the latest, most energy efficient systems, and it will issue technical white papers about heating and ventilating systems and related equipment. It will provide webinars and seminars, and will answer frequently asked and specific questions.

The Voltimum UK Partners currently involved are: BEAMA (Kelly Butler), Redring-Xpelair (Steve Mongan), Glen Dimplex (Karen Trewick and Chris Stammers), Horstmann (Tim Acton), and Vent-Axia (Adrian Williams, Jenny Smith), with other leading manufacturers and organisations soon to join. Kelly Butler chairs this new HVAC Expert Panel.

Among the many heating and ventilating topics currently of interest in the market are the follow following:

• Building Regulations Part G - sanitary hot water and water heating guidance
• Energy labelling for water heating
• The ErP Directive' (Energy-related Products) regarding fans and heaters
• Standard Assessment Procedures (SAPs).

Two of these topics are covered to some extent in this VoltiTECH.

1) Ventilation types:

There are a number of basic ventilation types, but the essential two are natural ventilation and mechanical ('forced').

• Natural ventilation - This uses the external air to ventilate a room or building without using a fan or other mechanical system. It can be achieved using opening windows and/or trickle vents (smaller systems), and in larger, more complex buildings, the 'stack effect' can be used, where cool outside air is drawn into the building naturally through low level openings. It then rises, ventilates, and passes out of upper vents to the outside again.
• Forced (mechanical) ventilation - With this method, room or building internal air is passed through an air handling unit (AHU) , which is a device used to condition and circulate air as part of a heating, ventilating, and air-conditioning HVAC system, or directly into the space by a motor-driven fan. Also, a strategically-placed exhaust fan can improve air infiltration or natural ventilation. In this way, forced ventilation controls indoor air quality so that excess humidity, smells and contaminants are diluted or removed.

A mechanical exhaust is typically used to control odours, vapours, air-bourn greases and humidity in kitchens and bathrooms. To obtain the best effect with greatest energy efficiency, it is important to specify or design the mechanical ventilation system taking into account flow rates (function of fan speed and exhaust vent size), and noise levels. Any exhaust ducting crossing unheated spaces should be insulated to prevent condensation on or in the ducting.

Ceiling fans do not provide ventilation, but merely circulate air within a room. However, they reduce the perceived temperature because they help evaporate perspiration. Note that ceiling fans can also be used to keep rooms fitted with them warmer in the winter by stratifying warm air from ceiling to floor.

Larger fans / AHUs can form part of building HVAC systems (which we are not looking at in this VoltiTECH), and there are also industrial fan types, which range in size from the small to the very large, and which are designed to withstand harsh environments and operating conditions.

Whole house ventilation:

A sub-division of mechanical ventilation (and one that is now almost a ventilation system in its own right) is whole house cooling. This method, in which air is drawn in from open windows and exhausted through the attic and roof, can substitute for an air conditioning system for most of the year.

Whole house fans should provide houses with 30 to 60 air changes/hour, and this - combined with ceiling fans and other circulating fans - can provide good domestic summer comfort. Note that a home's central heating and cooling system ducting can be modified to provide whole house cooling.

Just as importantly, and with Part L of the Building Regulations in mind, to obtain the highest energy efficiency, the homes of today should be fully insulated, be built as close as possible to airtight standards, and they should be fitted with a central ventilation system with heat recovery. At the same time, as buildings are being made increasingly air tight and thermally efficient, it is becoming essential to ventilate effectively to ensure that good indoor air quality is attained and maintained.

There are various types of whole house ventilation system (with a sometimes confusing number of different names and acronyms for them), but one of the most modern and important is mechanical ventilation with heat recovery (MVHR). With this technology, fresh air is continuously drawn into the home by a low energy ventilation unit, typically mounted within the roof space, although a utility room can also be used. Once passed through the heat exchanger within ventilation unit, warm, clean, fresh, filtered air is distributed around the home through ducting running to bedrooms and living rooms etc.

As the move towards zero carbon homes targets gathers pace, MVHR systems are beginning to gain a significant foothold in UK housing. Such systems can recover up to 90- 95% of the heat normally lost through open windows, trickle vents and extractor fans typically found in buildings.

Standard Assessment Procedures (SAP) is cited in Part L of the Building Regulations as a means of assessing dwelling performance (see the previous VoltiTECH for more information - link below). It is the Government's recommended system for measuring the energy performance of residential dwellings. As Vent-Axia has said, 'every point counts', and with SAP calculations, even half a point could contribute to a pass or fail in terms of the Dwelling Emission Ratings (DER).

Moving towards the Government's zero carbon home target, specification becomes harder as technology efficiency rates start to attain their maximum, yet as buildings become increasingly air tight and thermally efficient, it is more important than ever to ventilate effectively. It is considerations such as these that are driving the increasing adoption of MVHR systems, which provide a business opportunity for enterprising electrical contractors from this growth - following suitable training.

This is the background to legislation and technology designed to ensure healthy indoor air quality in tomorrow's new homes, especially as improvements to Building Regulations Part L require new homes to be built to increasing standards of air-tightness, which could adversely affect health - the tighter the buildings become, the more purpose-designed ventilation is needed.

Electric heating:

Electric heating, which is any process where electrical energy is converted to heat, has typical applications in water heating, space heating, industrial processes and cooking, among others. For the purposes of this VoltiTECH, we are looking primarily at water and space heating (plus ventilation).

• Electric water heating - Ignoring the electrode type of electric water heating, which can have safety issues, the main type still is immersion, in which a hot water cylinder contains an insulated electric resistance heater and a temperature sensor. Although some manufacturers say otherwise, the fact is that all electric resistance heaters are 100% efficient at point-of-use. There are also tank-less heaters and electric showers, in which the immersion heater is turned on by water passing through and turned off when the flow is stopped.
• Electric space heating - Electric space heating systems comprise domestic electrical underfloor types, and radiative, convection, fan and storage varieties. Note that off-peak storage heaters for a given property will always be cheaper to run over a 16 hour day than an electric convector heater or radiator using the standard rate electricity.
• Underfloor heating - With this, electric current flows through a flexible conductive heating element (cables, pre-formed cable mats, bronze mesh and carbon films). Because of their low profile, they can be installed in a thermal mass, or directly under floor finishes. This voltage of either 110V or 230V, or extra low voltage (8 to 30V) is applied to the electrical resistance heating element. The control unit typically contains a step-down transformer, and a floor thermostat controls the pre-set temperature. The floor heats the air, which circulates, heating the room spaces etc. Underfloor heating generally provides the most consistent room temperature from floor to ceiling compared to other heating systems.
• Heap pumps - Another form is the heat pump, in which an electric motor drives a refrigeration cycle, drawing energy from a source (usually the ground or external ambient air), and pumps it into the space to be heated. Note that this is an essentially reversible process, so heat pumps can also be used to cool spaces. Although heat pumps will not be suitable for every application, they are very energy efficient and are sometimes labelled 'sustainable'.

Modern control strategies:

Electric heating technologies may be for the most part mature, but just as with ventilation products, the drive for energy efficiency is bringing significant improvements to the control of heating devices and systems. Looking at the electrical heating system's responsiveness, this reflects the ability of the heater to match the heating needs of a home, which is important, not just from the perspective of the heater being able to warm a space well, but also from an energy efficiency perspective.

High energy efficiency and responsiveness combined with modern controls mean - for example - that users of storage heaters can use the stored heat as and when they need it. This is changing the peak / off-peak split of energy usage in storage heating. Being able to harness low-carbon, low-cost electricity saves end-users' money and supports demand side management. Dimplex is one company that is taking advantage of this with its new Quantum storage heater and sophisticated control system (for more information, see elsewhere in this VoltiTECH).

This is a very brief introduction and overview into a large topic, but in terms of informing users and helping them to make a choice, Dimplex has helped by providing elsewhere in this VoltiTECH, a PowerPoint entitled: 'Electric Heating Market - recent history'. Among many other fascinating things, this provides reasons to choose electric convectors or radiators.

Dimplex also says that there is a great deal of ignorance about the actual cost of using various electrical appliances, so has provided a short (three question) quiz concerning the cost per hour of using various electrical items. Look for it elsewhere in this VoltiTECH and take part; the results might surprise you!

Related articles:

To see many related articles on fans, ventilation, Part L of the Building Regulations, MVHRs, space heaters, heat pumps and boilers, please click on the links below:

VoltiTECH - HVAC and the Indoor Air Quality Report - www.voltimum.co.uk/news/17859/infopro.newsletter.bulletin/hvac-and-the-indoor-air-quality-report.html

Vent-Axia creating the right balance... - www.voltimum.co.uk/news/7222/consult.experts_hottopics.HVAC.Overview/vent-axia-creating-the-right-balance---.html

Dimplex supports installers on new heat pump standard - www.voltimum.co.uk/news/17809/consult.experts_hottopics.HVAC.Overview/dimplex-supports-installers-on-new-heat-pump-standard.html

MVHR: the time is now - www.voltimum.co.uk/news/12339/consult.experts_hottopics.HVAC.Overview/mvhr--the-time-is-now.html

Controlled ventilation helps homes save significant energy, says Voltimum - www.voltimum.co.uk/news/18702/consult.experts_hottopics.HVAC.Overview/controlled-ventilation-helps-homes-save-significant-energy---voltimum.html

Technical Guide - 'Best residential ventilation measurement practice for Part F compliance' by Vent-Axia - www.voltimum.co.uk/news/18655/consult.experts_hottopics.HVAC.Overview/technical-guide----best-residential-ventilation-measurement-practice-for-part-f-compliance----vent-axia.html

Zero Carbon Hub - Mechanical ventilation with heat recovery in new homes (interim report) - www.voltimum.co.uk/news/17815/consult.experts_hottopics.HVAC.Overview/zero-carbon-hub---mechanical-ventilation-with-heat-recovery-in-new-homes---interim-report.html

BEAMA - Mechanical ventilation with heat recovery; a new report boosts an already rising star - www.voltimum.co.uk/news/17812/consult.experts_hottopics.HVAC.Overview/beama---mechanical-ventilation-with-heat-recovery--a-new-report-boosts-an-already-rising-star.html

BEAMA - FAQs about heat pumps - www.voltimum.co.uk/news/17391/consult.experts_hottopics.HVAC.Overview/beama---faqs-about-heat-pumps.html

It's All About Electric - www.voltimum.co.uk/news/13732/consult.experts_hottopics.HVAC.Overview/it-s-all-about-electric.html

The true cost of a heating system - www.voltimum.co.uk/news/13733/consult.experts_hottopics.HVAC.Overview/the-true-cost-of-a-heating-system.html