LEVEL 4 BUILDING SERVICES TRAINING

1. LEVEL 4 BUILDING SERVICES TRAINING 2.0 - ADVANCED HEATING, DOMESTIC HOT WATER, VENTILATION AND LIGHTING

2. LEVEL 4 BUILDING SERVICES TRAINING District Heating Systems • Heat produced at one centralized source • Commonly Boiler station, steam boiler or CHP generator • Heat is distributed around the site by water or steam via a network of pipes, most commonly underground • If utilising CHP or waste heat from industry District Heating can be very energy efficient • Reduced plant requirements throughout site, reducing maintenance issues • High initial cost outlay

3. LEVEL 4 BUILDING SERVICES TRAINING Bristol City Council Community Heating BIOMASS & BIOFUEL BOILERS 

4. LEVEL 4 BUILDING SERVICES TRAINING District Heating Systems - CO2 Emission Factors • Should reflect average annual efficiency and fuel mix for whole of District Heating system • Includes all heat generating plant, including CHP or waste heat recovery • Effect of heat losses in distribution (external to building) • Emissions from electricity used for pumping • CO2 emission factors for fuel(s) used by system should be as set out in Table 2 of Approved Document L2A • For collection of data for EPCs, seek and document guidance from a suitably qualified person with regard the calculation of CO2 emission factors for district heating systems

5. LEVEL 4 BUILDING SERVICES TRAINING District Heating Systems - CO2 Emission Factors for systems supplied by CHP

6. LEVEL 4 BUILDING SERVICES TRAINING Domestic Hot Water (DHW) • Types of DHW can be categorised in two main types • Stored Hot Water systems; • Immersion Systems – A heating element is immersed in cylinder • Direct Boiler System – Water heated directly by boiler and stored in cylinder • This includes gas fired stand alone water heaters • Indirect Boiler System (Calorifiers) – A constant temperature heating circuit from the boiler enters a coil within the storage cylinder on a closed loop. • On-Demand (instantaneous) Hot Water systems • Thermal Store System – LTHW is sent from the boiler to a cylinder on its way to heating the building, creating a store of hot water. Mains cold water passes through a heat exchanger in the thermal store providing mains pressure hot water very efficiently • Single Point Water Heater – Either gas or electric, located near water outlet • Multi-point Water Heater – A combination boiler is the best example of this type of system. Used to provide hot water to multiple outlets

7. LEVEL 4 BUILDING SERVICES TRAINING

8. LEVEL 4 BUILDING SERVICES TRAINING Domestic Hot Water (DHW) • Storage Losses in Storage Systems • There is a heat loss associated with storage systems that relates to the insulation of the cylinder, and its capacity • When inputting information, use manufacturers details where possible, if no information is available enter the storage capacity for default values to be applied • Secondary Circulation • To prevent ‘dead-legs’ where hot water stands stagnant, and may cool to levels where Legionella can develop, secondary circulation returns hot water to the storage cylinder • The pump power relating to the secondary circulation should be established from manufacturers data. Where not available use default values • Secondary circulation losses relate to loss of heat per unit length of pipework, measured in W/m.

9. LEVEL 4 BUILDING SERVICES TRAINING Ventilation Strategies • Natural Ventilation • Single-sided and Cross ventilation • Stack ventilation • Stack/Wind ventilators • Mechanical Ventilation • Supply Only ventilation • Supply and Extract systems • Mixed Mode ventilation • Heat Recovery devices

10. LEVEL 4 BUILDING SERVICES TRAINING Natural Ventilation • Single-sided Ventilation • Simplest form of ventilation • Minimal cost • Generally suitable for a depth of 6-7m from perimeter • Depends on presence of wind for good ventilation • Ventilation only available by opening windows, even in cold weather or times of noise disturbance • Cross Ventilation • High rate of ventilation possible • Can be used in deep plan offices • Good occupant control • Clear air path required in the space • Same problems with opening windows

11. LEVEL 4 BUILDING SERVICES TRAINING Natural Ventilation • Stack Ventilation • Temperature difference becomes driving force, rather than wind speed • Effective for night time cooling • Can be combined with cross ventilation in correct weather conditions • Stack ventilation will only work with lower external air temperature • Stack ventilation should be considered as a Level 5 attribute as Dynamic Simulation Modelling (DSM) software is best suited to accurately reflect the effects of the stack ventilation • Stack/Wind ventilators utilise wind to drive air into building and rely on stack effect to exhaust air

12. LEVEL 4 BUILDING SERVICES TRAINING Single-sided ventilation Cross ventilation Stack ventilation on a still day

13. LEVEL 4 BUILDING SERVICES TRAINING Mechanical Ventilation • Supply Only ventilation • Used primarily with roof mounted warm air units or perimeter fan coil units to directly heat supply air • Can be used as a cooling mechanism to purge stale, warm air through the night • Used to provide combustion air to boiler plant within plant rooms • Enables fresh air to be filtered and heated, and ensures adequate supply of fresh air into space • No opportunity to recoup heat from exhaust air by heat recovery

14. LEVEL 4 BUILDING SERVICES TRAINING Mechanical Ventilation • Supply and Extract systems • Provides equal measures of supply and extract air, ensuring adequate levels of fresh air are always provided • Ability to use heat recovery to improve energy efficiency • Removed requirement for opening windows, improving noise levels and security • Fully ducted system increases installation and maintenance costs • Fans consume additional energy • Mixed Mode ventilation • Describes system that utilises both natural and mechanical ventilation • Perimeter areas of deep plan rooms can utilise natural ventilation, with mechanical ventilation serving the remaining area • Mechanical element can be extract, supply or a combination of the two

15. LEVEL 4 BUILDING SERVICES TRAINING Mixed Mode Examples

16. LEVEL 4 BUILDING SERVICES TRAINING Mechanical Ventilation Heat Recovery devices • Plate heat exchanger (recuperator) • Typically cross flow heat exchanger – Up to 60% efficient • Transfers heat directly from exhaust to supply air • Counter current heat exchangers can provide up to 99% efficient heat transfer • Rotary heat exchanger (Thermal Wheel) • Most Efficient heat recovery • Cannot be used where odour or bacteria transfer are critical (hospitals) • Run-around coil • Typically 45-55% efficient • Uses water (or water/glycol mix) as heat transfer medium

17. LEVEL 4 BUILDING SERVICES TRAINING Thermal Wheel Heat Exchanger Counter Current Plate Heat Exchanger types

18. LEVEL 4 BUILDING SERVICES TRAINING Air Handling Unit (AHU) CEN Leakage Standards • If the AHU has been tested, or design target set, to meet CEN Standard, select appropriate CEN (comite’ Europe’en de normalisation) classification within iSBEM • If surveying existing building information relating to leakage standards is not available, leave as default • The CEN classes L1, L2, L3 for air handling units correspond to the Eurovent [1] classes C, B, A respectively. • The proposed leakage classes correspond to the previous EN 1886 AHU classes A (L3), B (L2) and C (L1), tested at 400 Pa negative.

19. LEVEL 4 BUILDING SERVICES TRAINING Specific Fan Power • Relates to the circuit-watts used by the air distribution system, inclusive of losses through switchgear or controls, for the supply and extract fans, relative to the design flow rate through the system (W/l/s) • See, Non-Domestic Heating, Cooling and Ventilation Compliance Guide. CLG, for further guidance on calculation Specific Fan Power

20. LEVEL 4 BUILDING SERVICES TRAINING Metering Provisions • For new buildings, since April 2006, Approved Document L2A states; • Reasonable Provision for energy meters would be to install energy metering systems that enable; at least 90% of the estimated annual energy consumption of each fuel to be assigned to the various end use categories (heating, lighting etc); and • The performance if any LZC system to be separately monitored; and • In buildings with a total useful floor area greater than 1000m2, automatic meter reading and data collection facilities. • 5% improvement applied within SBEM if metering provision warn ‘out of range’ values • Detailed guidance can be found in supporting document CIBSE TM39

21. LEVEL 4 BUILDING SERVICES TRAINING Building Management Systems (BMS) • Moderate to highly serviced buildings often have BMS • Networked control system with a permanent operator terminal (PC) • Allows monitoring and control of building services plant • Allows manipulation of set points (temperatures, time profiles etc) • User friendly interface provided by graphical representation • Advantages; • Allows precise control of systems to improve internal conditions • Can incorporate user controls • Plant performance can be monitored over time • Limitations; • Upgrades can be tied to specific manufacturers • Optimum performance requires training of operators

22. LEVEL 4 BUILDING SERVICES TRAINING Lighting • Air Extracting Luminaries • Removes requirement for extract grilles, allowing air to be removed from the space through an aperture within the light fitting • This removes heat generated by the lamps before it can impact on the space, ensuring lower cooling loads leading to reduced energy use • Generally Air Extracting Luminaries will be used where a ceiling void is used as a effective plenum for extract ventilation

23. LEVEL 4 BUILDING SERVICES TRAINING Lighting Controls • Photoelectric Control (Daylight linking) • Photocells either within the fitting or within an occupancy/daylight sensor mounted on the ceiling detects level of daylight within the space • Depending upon the lighting design, lamps may be dimmed or switched off when sufficient levels of daylight are available • Typical for perimeter bank of fittings only to be controlled by photocells • Control system uses power, referred to as ‘Parasitic Power’. Unless known use default value for either stand alone or addressable system • Occupancy Sensing • Passive infra-red sensors detect movement and activate lighting • Auto On-Off: Lights turn on when sensor recognises occupancy and off after a time period after last presence was detected • Manual On-Auto Off: Manual switching used to turn lights on, automatically turn off once presence no longer detected

24. LEVEL 4 BUILDING SERVICES TRAINING Power Factor • Power Factor • The power factor of an AC electric power system is defined as the ratio of the real power to the apparent power, and is a number between 0 and 1, where 1 is referred to as unity • Electrical loads consuming AC power consume both real power, which does useful work, and reactive power, which dissipates no energy in the load and returns to the source on each alternating current cycle • Power Factor Correction (PFC) • The process of adjusting the characteristics of electric loads in order to improve power factor so that it is closer to unity • Passive PFC • Simple way of correcting nonlinearity of load using capacitor banks • Active PFC • Power electronic system that controls amount of power drawn by load to correct power factor closer to unity • More effective than Passive PFC

25. LEVEL 4 BUILDING SERVICES TRAINING ANY QUESTIONS OR FEEDBACK