Presentation on theme: "Energy Performance Certificates"— Presentation transcript:
1Energy Performance Certificates HeatingPRESENTED BY
2LEVEL 3 BUILDING SERVICES TRAINING HEATING SYSTEMSThere are many varied forms of introducing heat to occupied areas, this guide will detail the most common forms of heating system likely to be found in buildings suitable for a Level 3 assessment.To have an improved understanding of the types and operation of systems, some definitions require to be addressed
3LEVEL 3 BUILDING SERVICES TRAINING Direct & Indirect Heating SystemsDirect SystemsThese are where the fuel is burned directly to give heat output, for example gas fired unit heaters, electric panel heaters, gas fires etc.
4LEVEL 3 BUILDING SERVICES TRAINING Indirect Heating SystemsThis is where the fuel is burned by a boiler or other heat producing device to heat another media (water / air) which is then transported to a terminal device to give a heat output (radiators, fan convectors, grilles etc.).
5LEVEL 3 BUILDING SERVICES TRAINING Radiant and Convective HeatingConvective HeatingConvective heating systems use the movement of warm air to transfer heat. This air movement can be induced by natural convection or by the use of fans, for example via:Fan convectorsFloor or ceiling-mounted unit heatersCentral air-handling plant.
6LEVEL 3 BUILDING SERVICES TRAINING Radiant HeatingRadiant heating systems use infrared radiation to heat the building’s occupants and its fabric directly, without the need for warm air as a transfer medium. They are particularly useful for heating large volumes with high ceilings, typical of industrial buildings. Radiant systems can also provide local ‘spot heating’, and are also particularly efficient in buildings with high air change rates.
7LEVEL 3 BUILDING SERVICES TRAINING Boilers There are many types sizes and outputs available using various fuel types to suit every type of Low Pressure Hot Water (LPHW) application, whether these are simple singular wall mounted applications to multiple floor mounted installations, the same process is occurring, Water is being heated and circulated to provide useful heat. The boiler provides an indirect source of heat to be distributed through pipework systems which is then discharged to the space by means of radiators, convertors radiant panels or similar. The most common forms of heating devices likely to be assessed are described later within the training course
8LEVEL 3 BUILDING SERVICES TRAINING Atmospheric vs. Condensing A condensing boiler is a high efficiency modern boiler that incorporates an extra heat exchanger so that the hot exhaust gases lose much of their energy to pre-heat the water in the boiler system. When working at peak efficiency, the water vapour produced in the combustion process condenses back into liquid form releasing the latent heat of vaporisation. The efficiencies of this type of boiler are fully dependant on the flow and return temperatures of the media heated.
9LEVEL 3 BUILDING SERVICES TRAINING Wall Mounted BoilersThis type of boiler is not dissimilar to what is likely to be found In a domestic home, however these generally have a higher output and will have components such as expansion vessels and pumps mounted remotely from the boiler itself.
11LEVEL 3 BUILDING SERVICES TRAINING Wall Mounted Multiple Boiler InstallationsThis type of installation has become more common over the past few years and is generally used in larger applications where one boiler is not capable of providing the required load, or where a back-up is required.These units can be controlled on a duty / share operation which will be covered in further detail under the controls section
13LEVEL 3 BUILDING SERVICES TRAINING Floor Mounted BoilersFloor mounted boilers will generally be found in older developments or where larger heat outputs are required. These can also be installed in multiple arrangements to increase loads and provide back-up facilities
16LEVEL 3 BUILDING SERVICES TRAINING Boiler EfficienciesCare should be taken when assigning boiler efficiencies to produce the Energy Performance Certificate. Manufacturers will advise efficiencies well in excess of 90%, and although this is achievable it can only be obtained under specific flow and return (F&R) conditions, especially in the case of condensing boilers.Follow the LATEST conventions
17LEVEL 3 BUILDING SERVICES TRAINING Distribution Systems (WET SYSTEMS)RadiatorsAlthough delegates on this course will have knowledge of domestic wet heating systems using radiators, the following diagrams detail more complex installations to be found in commercial premises-
18LEVEL 3 BUILDING SERVICES TRAINING Radiators and convectors are the principal means of heat emission in most buildings. Less popular alternatives include exposed pipes and radiant panels for use in warehousing, workshops and factories. where appearance is not important. Embedded panels of pipework in the floor screed can also be used to create 'invisible' heating, but these have a slow thermal response as heat energy is absorbed by the floor structure.Despite the name radiator. no more than 40% of the heat transferred is by radiation. The remainder is convected, with a small amount conducted through the radiator brackets into the wall.
20LEVEL 3 BUILDING SERVICES TRAINING Originally. radiators were made from cast iron in three forms: Hospital. Column and Panel. Hospital radiators were so called because of their smooth. easy to clean surface, an important specification in a hygienic environment. Column radiators vary in the number of columns. The greater the number, the greater the heat emitting surface.Cast iron radiators are still produced to special order. But replicas in cast aluminium can be obtained. Cast iron panels have been superseded by pressed profiled steel welded panels. These are much slimmer and easier to accommodate than cast iron in the modern house. In addition to the corrugated profile. finned backing will also increase the heating surface and contribute to a higher convection output. Pressed steel radiators are made in single. Double and triple panels.
22LEVEL 3 BUILDING SERVICES TRAINING Radiant & Convector Skirting Heaters Radiant and convector skirting heaters are unobtrusive at skirting level and provide uniform heat distribution throughout a room. Natural convectors have a heating element at a low level within the casing. This ensures that a contained column of warm air gains velocity before discharging to displace the cooler air in the room. Fan convectors may have the heater at high level with a variable speed fan located below. In summer. the fan may also be used to create air circulation. Overhead unit heaters are used in workshops to free the wall space for benches, machinery. etc.
23LEVEL 3 BUILDING SERVICES TRAINING A variation may be used as a warm air curtain across doorways and shop entrances.Individual unit heaters may have a thermostatically controlled inlet valve or a bank of several units may be controlled with zoning and diverter valves to regulate output.
24LEVEL 3 BUILDING SERVICES TRAINING Radiant heating systems use infrared radiation to heat the building’s occupants and its fabric directly, without the need for warm air as a transfer medium.They are particularly useful for heating large volumes with high ceilings, typical of industrial buildings. Radiant systems can also provide local ‘spot heating’, and are also particularly efficient in buildings with high air change rates
25LEVEL 3 BUILDING SERVICES TRAINING Radiant heating systems offer the following benefits relative to convective types and are often the first choice for industrial buildings: Energy consumption can be lower, as a result of:Generally lower air temperaturesReduced stratification at high levelDirectional output delivers heating directly to where it is neededRapid warm-upResponsive controlNo air movement.
26LEVEL 3 BUILDING SERVICES TRAINING Radiant Panels Served by BoilerLEVEL 3 BUILDING SERVICES TRAINING
27LEVEL 3 BUILDING SERVICES TRAINING Underfloor Heating SystemsUnderfloor heating is far from a new concept, it was first used by the Romans whose dwellings were constructed with voids through which air, warmed by an open fire, would pass thus heating the structure.In the more recent past electric heating elements were buried within floor screeds. These were heated over night using 'cheap rate' electricity. However, the building would overheat during the day but in the evening, when heat is generally required, no further heat was available.
28LEVEL 3 BUILDING SERVICES TRAINING Utilising today's modern multilayer pipes, control systems and high efficiency boilers, the underfloor heating systems of today are extremely comfortable and controllable.Radiators are no longer needed so giving more room space.The heat is more evenly distributed and dust is not circulated. Underfloor heating from the whole floor area of the house gently warms the air above, eliminating cold spots.The warm air convects from the floor surface losing approximately 2 degrees centigrade at 2.0 meters above the floor.
29LEVEL 3 BUILDING SERVICES TRAINING Independent tests reveal that the most acceptable indoor climate is one in which the floor temperature ranges between 19-29°C and the air temperature at head level ranges between 20 and 24°C.With radiator or convector heating systems a vertical temperature gradient is produced; colder at foot level than at the head. Underfloor heating has made it possible to reduce energy consumption by using low water temperatures. These systems, based on the development of complex and very high quality plastic pipe, such as the multilayer pipe, now account for over 60% of some European heating markets
30LEVEL 3 BUILDING SERVICES TRAINING Underfloor heating systems are suitable for both domestic and commercial applications. It has a particular advantage in public areas where exposed hot surfaces can be dangerous. Gas, oil or solid fuel boilers can be used as the source of heat for any underfloor heating system. Condensing boilers being particularly suited as the operation of underfloor heating systems allows them to operate in their most efficient manner.
31LEVEL 3 BUILDING SERVICES TRAINING It is possible to combine both underfloor systems with radiator systems. For example, the ground floor could be heated by an underfloor system whilst the 1st floor is heated using a wet radiator system or radiators can be fitted in the bathroom and lavatory in homes where the main system is underfloor heating.
33LEVEL 3 BUILDING SERVICES TRAINING Ducted Warm Air SystemWarm air can be used as an alternative to hot water in pipes. There are no obtrusive emitters such as radiators. Air diffusers or grilles with adjustable louvres finish flush with the ceiling or floor. The heat source may be from a gas, oil or solid fuel boiler with a pumped supply of hot water to a heat exchanger within the air distribution unit. The same boiler can also be used for the domestic hot water supply. Alternatively, the unit may burn fuel directly, with air delivered around the burner casing. Control is simple using a room thermostat to regulate heat exchanger and fan.
35LEVEL 3 BUILDING SERVICES TRAINING Positioning grilles in doors is an inexpensive means for returning air to the heater. but a return duct is preferred. Fresh air can be supplied to rooms through openable windows or trickle ventilators in the window frames. If rooms are completely sealed, fresh air should be drawn into the heatinq unit.
38LEVEL 3 BUILDING SERVICES TRAINING Distribution Systems (DIRECT RADIANT)Gas fired radiant tube heater
39LEVEL 3 BUILDING SERVICES TRAINING Distribution Systems (DIRECT RADIANT)Gas fired radiant tube heater
40LEVEL 3 BUILDING SERVICES TRAINING Gas fired plaque heater
41LEVEL 3 BUILDING SERVICES TRAINING Gas fired plaque heater
42LEVEL 3 BUILDING SERVICES TRAINING Electric Quartz radiant lamp: Efficiency 100% (1.0)
43LEVEL 3 BUILDING SERVICES TRAINING Electric Quartz radiant lamp: Efficiency 100% (1.0)Follow LATEST conventionsLosses are in power station and transmission
44LEVEL 3 BUILDING SERVICES TRAINING Distribution Systems (DIRECT CONVECTIVE)
45LEVEL 3 BUILDING SERVICES TRAINING Distribution Systems (DIRECT CONVECTIVE)
46LEVEL 3 BUILDING SERVICES TRAINING Floor Standing Unit Heater
47LEVEL 3 BUILDING SERVICES TRAINING Floor Standing Unit Heater
48LEVEL 3 BUILDING SERVICES TRAINING EfficienciesGenerally direct fired gas or oil appliances have good efficiencies and most of the new modern types are listed on the ECA (Enhanced Capital Allowance Scheme).However, actual percentage efficiencies should be sought from manufacturers data, if this data cannot be collected, the default values within the SBEM interface software should be used.
49LEVEL 3 BUILDING SERVICES TRAINING De-Stratification FansWith any conventional heating system, natural convection increases the temperature gradient.This results in the ambient temperature at the apex of the roof being greater than the required design temperature in the occupied zone at floor level
51LEVEL 3 BUILDING SERVICES TRAINING By using a system of destratification fans, the hot air in the roof space is directed down to the required area, thus reducing the heating load
52LEVEL 3 BUILDING SERVICES TRAINING These unit are operated by a thermostat to switch the fans off or on dependent upon the temperature settings of the thermostat and the internal room temperatures. These fans are also useful in summertime to reduce cooling loads.