Transcript Thermal loss of building envelope

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Heating, ventilation and energy efficiency in buildings in Finland
Finnish regulations are in general based on European Union legislation
and directives in all European Union countries:
Directive 2010/31/EU of the European Parliament and of the Council
of 19 May 2010
on the energy performance of buildings
(recast) EPBD
There are also a lot of other directives related to energy in European
Union.
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Heating, ventilation and energy efficiency in buildings in Finland
National building code D3, Energy efficient of buildings,
decree of the Ministry of the Environment containing regulations and
guidelines
Content in general
1. General and definitions
2. Energy efficiency requirements
3. Basic data for energy calculations
4. Calculations rules
5. Evidence of conformity
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Heating, ventilation and energy efficiency in buildings in Finland
National building code D3, decree of the Ministry of the Environment
Valid version July 2012 came in force in new buildings concerning buildings
divided in 9 categories (SCOPE....):
1. One family houses, terrace (row) houses, linked houses
2. Blocks of flats (multi-storey residential buildings)
3. Office buildings
4. Commercial buildings
5. Accommodation buildings
6. Educational and nursery (kindergarten) buildings
7. Gym buildings excluding indoor swimming pools and ice-skating rinks
8. Hospitals
9. Other buildings
Usually industrial buildings and holiday cottages are excluded, why?
Definitons: necessary to read so that you could understand D3
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Heating, ventilation and energy efficiency in buildings in Finland
National building code D3, decree of the Ministry of the Environment
Newest version July 2012 (EU names):
(a) single-family houses of different types;
(b) apartment blocks;
(c) offices;
(d) education buildings;
(e) hospitals;
(f) hotels and restaurants;
(g) sports facilities;
(h) wholesale and retail trade services buildings;
(i) other types of energy-consuming buildings.
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Heating, ventilation and energy efficiency in buildings Finland
System boundary of delivered energy
RENEWABLE SELFSUSTAINING (AUTOTROPHIC)
ENERGY (ON-SITE)
Solar and internal heat gains (heat
gains from humans)
PURCHASED ENERGY
NET ENERGY NEED
ENERGY DEMAND OF SPACES
Heating
Cooling
Ventilation
Hot domestic water
Lighting
Appliances / consumer devices
(electrical)
Persons
TECHNICAL SYSTEMS
heating energy
district heating
Losses in systems and
conversions (like
burning of fuels)
cooling energy
electricity
district cooling
fuels
electricity
renewable and
non-renewable
HEAT LOSSES
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Heating, ventilation and energy efficiency in Finland
Finnish text figure
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Heating, ventilation and energy efficiency in buildings in Finland
Energy efficiency requirements for new buildings
•Total energy consumption of the building
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The net purchased energy must be calculated with standard use and with real
design measures of the building
The total energy consumption, E-value, must be calculated and the energy form
coefficients are used
•E-value has limits for each type of the buildings (categories)
•Controlling of room temperature during summer
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Overheating and too high indoor temperatures must be avoided primarily with
correct design of the building (passive methods and night ventilation)
E.g. solar protection, size and surface + orientation of windows
If cooling is necessary the energy of cooling is added to E-value as well
Room temperature must be calculated for typical spaces and rooms,
limits +25 / 27 °C not to exceed more than 150 degree hours
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Heating, ventilation and energy efficiency in buildings in Finland
Air tightness of the building envelope
•
Air tightness of the building envelope and between different spaces that leakage air
do not cause significant harm for persons or building structures or energy efficiency
The air leakage value of the building envelope must not be more than 4
m³/h,m² (best new buildings less than 1 easily)
•
Air tightness can be measured and then calculated for the E-value
Thermal insulation of the building envelope
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Max values for wall, roof, floor, door and windows
Reference values in table 2.5.4
Thermal loss of the building
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The thermal loss of the building envelope, the leakage air and ventilation is limited
The thermal loss must not exceed the thermal loss calculated with the reference
values (compensation calculations, design case and reference case)
Both cases are calculated with the real measures of the building
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Heating, ventilation and energy efficiency in buildings in Finland
The specific thermal loss of the building envelope
•
Formula 1 in Chapter 2.5.3
The specific thermal loss of the leakage air of the building
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Formula 2 in Chapter 2.5.6
The specific thermal loss of ventilation of the building
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Formula 3 in Chapter 2.5.9, for reference value is used ηa= 45 %
The design case ηa is calculated according to the real design case values for the
weather zone 1
Design case thermal loss is calculated then according to Table 2 and 3
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Heating, ventilation and energy efficiency in buildings in Finland
Energy efficiency of the ventilation system
•
The specific fan power values 2,0 kW/m³/s (for supply and exhaust systems) and 1,0
kW/m³/s (only exhaust ventilation) must not be exceeded (fan power = electricity)
45 % of the heat needed for ventilation air must be recovered with heat recovery from
exhaust air or with the corresponding reduction of necessary heat energy of:
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1) improving of the building insulation of the building envelope,
2) improving the air tightness of the building envelope or
3) reducing the quantity of heat necessary for the heating of the ventilation in other
ways than recovering the heat from the extract air
Heating power dimensioning must be able to keep the correct room
temperatures during dimensioning conditions.
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Heating, ventilation and energy efficiency in buildings in Finland
Measuring energy consumption
The following energy quantities must or should be able to measure easily
• Total electricity of the building (normally always)
• Purchased heat energy for the building
• HDW is measured
• Ventilation electricity is measured and possible to measure power demand
• Cooling electricity is measured and it should be easy to measure momentary electrical
power demand and produced cooling energy
• Fixed lighting system energy is measured
Temporary buildings
Requirements are those for semi-warm buildings
Holiday homes (no limit for area, m²)

Less strict values for building envelope, no requirements for specific heat losses of air
tightness and ventilation
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Heating, ventilation and energy efficiency in buildings in Finland
Initial data for energy calculation
E-value is calculated with Weather zone 1 data
Indoor climate
• Room temperatures and air flow rates are taken from Table 2 for all buildings except
Category 9 buildings
• During other than the normal operation time is used min. 0,15 dm³/s, m²
Standard use and internal thermal loads
• Standard use and corresponding thermal loads from Table 3
Electricity usage (thermal loads) are calculated with the Formula 4
• if lighting is controlled by building automation this can be taken into account
(reduces electricity consumption of lighting)
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Heating, ventilation and energy efficiency in buildings in Finland
Initial data for energy calculation (2)
Hot domestic water
• Thermal loads from HDW storage and circulation: 50 % of calculated thermal losses
will come as internal thermal loads
• Table 4 (5) presents the specific HDW consumption and corresponding energy
demand
Airtightness of the building envelope
• In E-value calculations is used design case value for airtightness
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Heating, ventilation and energy efficiency in buildings in Finland
Calculation rules
Purchased energy
• with Chapter 3 initial data and design case measures, constructions and ηa
• with Chapter 4 rules
• with the requirements for tools in Chapter 5 and the presentation according to
Chapter 5
• No special spaces (like restaurants, laboratories or similar) are taken into account
• One family houses and other buildings having single use in the whole building can be
calculated as one calculation zone
• Bigger buildings are divided into different calc. zones according to the use and
purpose of the building and part of it
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Heating, ventilation and energy efficiency in buildings in Finland
Net demand of the heating energy
Net demand of heating energy calculations for spaces consists of
• + conduction heat losses
• + heat losses of leakage air
• + make up air and supply air heating in spaces
• - solar heat gains / thermal loads
• - internal heat loads
Net heat demand of ventilation is calculated
• + heat demand of ventilation (total)
• - heat recovery energy
• - defrost losses of heat recovery energy
• annual energy efficiency of ventilation system ηa including heat recovery is calculated
with the design case data
In solar heat loads is taken into account shading
• of adjacent buildings and trees
• venetian blinds
• awnings etc.
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Heating, ventilation and energy efficiency in buildings in Finland
Thermal losses of the building envelope
Conduction heat losses
• through walls, floors, roofs, windows, doors, skylight
• thermal bridges of joints
• ground under the building and crawling space are taken into account
Leakage air flow rate calculation
• Formula 5
Heating system
Heating system energy consists of heating of spaces, ventilation air and HDW and all kind
of system losses are taken into account like:
• distribution and emission losses
• production and storage losses
• conversion losses
• HDW storage and circulation losses
• electricity needed in previous systems (pumps…)
Net heating energy divided with different efficiencies presented in D5 (boilers, heat
pumps and so on)
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Heating, ventilation and energy efficiency in buildings in Finland
Some cases
Heat accumulating fireplace
• 2000 kWh / year
Air-to-air heat pump
• 1000 kWh / year
Residential spaces with hot water heating and electrical under floor heating in bathrooms
etc.
• 50 % of heating energy is considered to be electrical underfloor heating energy
With heat pumps the extra electrical energy needed during the coldest periods is taken
into account, if the heat pump is dimensioned for full / max. power demand at the
dimensioning conditions.
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Heating, ventilation and energy efficiency in buildings in Finland
Ventilation systems
Air flow rates and operation times in accordance with 3.3. and 3.4
• ηa calculated prior to this calculation
Ventilation electrical energy
• according to pressure losses (fan head), fan efficiencies and other equipment
efficiencies
Cooling systems
The energy use of the cooling system e.g. with the simplified method described in D5
Electricity use of lighting and consumer appliances / devices
In accordance with Chapter 3.3
• Formula 4
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Heating, ventilation and energy efficiency in buildings in Finland
Evidence of conformity
Energy declaration
• must be appended to building permit application
• must be verified before commissioning by the chief designer
Energy declaration includes the following:
• E-value (Chapter 2.1)
• Initial data and results of calculations (Chapter 5.3)
• Summer season temps and degree hours, cooling power (Chapter 2.3)
• Conformity with the regulations of thermal losses (Chapter 2.4)
•
Heating power demand at dimensioning conditions
• Energy certificate for the building
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Heating, ventilation and energy efficiency in buildings in Finland
Requirements for calculation tools
The tool must be able to calculate at least:
• net heating energy demand
• net cooling energy demand, if there is a cooling system in the building
•
Buildings without cooling or cooling in some spaces only:
• calculations can be based on simplified monthly basis, e.g. D5 method
All other buildings:
• the calculation tool must be able to handle heat storage and release (heat
accumulation to construction), dynamic calculation method like IDSA ICE software
Summer season room temperature:
• the calculations must be made with dynamic calc. tool
Presentation of results:
• central initial data and results must be presented according to Table 12 in Appendix 3
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Heating, ventilation and energy efficiency in Finland
D3 chapter 2: Total delivered energy consumption of a building
E-indicator is calculated with the following energy form coefficients (use
of primary energy)
• electricity 1,7
• district heating 0,7
• district cooling 0,4
• fossil fuels 1,0
• renewable fuels used in building 0,5
On-site renewable energy decreases delivered energy.
Examples of E-value according to D3 (2012)
 office building 170 kWh/m²,a
 block of flats 130 kWh/m²
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Heating, ventilation and energy efficiency in Finland
Control of summertime indoor temperatures
Primary methods to avoid harmful indoor temperatures are
•passive methods like placing and orientation of spaces and also
internal and external heat gains / loads must be taken into account
•night time ventilation
•solar shading
Hours / time of higher temperatures (25 or 27 °C) must be less than
150 hours between 1.6. – 31.8.
Calculations of indoor temperatures are made for worst cases (spaces
with high internal and external heat loads)
If cooling is necessary it increases energy consumption and E-indicator
rises.
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Heating, ventilation and energy efficiency in Finland
Air tightness of the building envelope
•building must be enough air tight so that unnecessary air flows are
avoided
•especially joints between different constructions and tightness of
through holes
•air leakage value of the building envelope q50 must not exceed 4
m³/h,m²
•in compensation calculations the reference value of q50 = 2 m³/h,m²
•in heat loss calculations q50 = 4 m³/h,m² if tightness is not specified or
measured
•air tightness is referred to pressure difference 50 Pa inside/outside
the building
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Heating, ventilation and energy efficiency in Finland
Thermal conductivity of building envelope constructions
Calculation: NBC D3, Formula (1)
Max. values of building envelope heat transfer coefficients 2012 NBC
used in compensation calculations...
•wall 0,17 W/m²,K
•log wall 0,40 W/m²,K
•roof and base abutting outside air 0,09 W/m²,K
•base floor abutting crawling space 0,17 W/m²,K
•building component against ground 0,16 W/m²,K
•windows, doors and skylights 1,0 W/m²,K
N.B. Article in The Rehva European HVAC Journal 6/2010 page 41...
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Heating, ventilation and energy efficiency in Finland
Thermal loss of the building
Thermal loss of envelope, leakage air and ventilation is limited in
order to achieve good energy efficiency.
Conformity of thermal loss is shown with calculation of compensation.
(Specific) Thermal loss of building envelope (Formula 1)
Max. values of building envelope heat transfer coefficients 2012 NBC
used in compensation calculations...
•wall 0,17 W/m²,K
•log wall 0,40 W/m²,K
•roof and base abutting outside air 0,09 W/m²,K
•base floor abutting crawling space 0,17 W/m²,K
•building component against ground 0,16 W/m²,K
•windows, doors and skylights 1,0 W/m²,K
Reference window area is 15 % of floor area above ground.
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Heating, ventilation and energy efficiency in Finland
Thermal loss of the building
(Specific) Thermal loss of leakage air (Formula 2)
The reference thermal loss of leakage air is calculated with the
reference value of q50 = 2 m³/h,m²
Thermal loss of design solution is calculated with q50 = 4 m³/h,m² , if it
not shown to be better e.g. pressure test or quality control system
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Heating, ventilation and energy efficiency in Finland
Thermal loss of the building
(Specific) Thermal loss of ventilation (Formula 3)
•Each air handling unit is calculated separately if necessary.
•Ventilation is calculated with standardized air flow rates and
operating times in both cases (reference and design)
•Reference value of annual energy efficiency of ventilation heat
recovery is 45 %.
•Design case: real values of design case are used when calculating
annual energy efficiency of ventilation heat recovery ηa for weather
zone 1
•(usually e.g. StPb climate, efficiency better than 45 %)
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Heating, ventilation and energy efficiency in Finland
Energy efficiency of ventilation system SFP
•specific fan power 2,0 kW/(m³/s) in supply and exhaust air systems
•specific fan power 1,0 kW/(m³/s) in exhaust air systems
If value of annual energy efficiency is less than 45 % it can be
compensated in total with
•better U-values
•better air tightness to meet the requirements
•reducing heat needed e.g. with preheating of outdoor air with heat
from ground and thus protecting freezing of exhaust air moisture in
heat recovery
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Heating, ventilation and energy efficiency in Finland
Energy measurements in buildings (2.11 English version)
•total electricity consumption of a building is measured
•purchased heating and cooling energy is measured
•domestic hot water of others than class 1 buildings is measured
•ventilation electricity is measured separately
•cooling electricity is measured separately
•cooling system must be designed and installed so cooling energy and
power demand can be easily measured
•lighting electricity is measured separately
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Heating, ventilation and energy efficiency in Finland
Initial / basic data for energy calculation (Chapter3)
•total energy consumption and summertime indoor temperature is
calculated with the weather data of zone 1 given in the appendix 2
Indoor climate is standardized (table 2)
• outdoor air flow rates
• in cases with demand controlled ventilation design values are
used
• heating limit temperatures
• cooling limit temperatures
•3.3 Standard use and internal heat gains / loads are given in Table 3...
Annual heat loads of lighting and devices Q (Formula 4)
Domestic hot water (3.4)
•standardized values for hot domestic water is given in Table 5
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Heating, ventilation and energy efficiency in Finland
Rules for energy calculations, general (Chapter 4)
•net delivered / purchased energy is calculated according to basic data
and standardized use
•restaurants, cafeterias, laboratories etc. are not taken into account in
calcs
•special systems like professional kitchen equipment, outdoor lighting,
elevators, defrosting of surfaces, pipes etc. are excluded
•small houses and other buildings for single use can be calculated as
one zone
•larger buildings can be divided in different zones according to their
purpose and operating time
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Heating, ventilation and energy efficiency in Finland
Rules for energy calculations, net heating energy demand (net delivered
/ purchased energy)
•principle: heat losses minus heat gains = need
•calculations consist of heat losses through building envelope, leakage
air flows and ventilation heat losses
•in calculations of solar heat gains solar shading (artificial and natural)
are taken into account
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Heating, ventilation and energy efficiency in Finland
Rules for energy calculations, net heating energy demand (net delivered
/ purchased energy)
Heat losses of building envelope
•with internal measures of the building
•thermal bridges are taken into account (e.g. C4 2012 methods and
instructions)
•leakage air heat losses (equation (5))
•heating systems; losses of heat emitters, distribution systems,
production, conversion, storage and electricity of auxiliary devices are
taken into account and are taken into account
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Heating, ventilation and energy efficiency in Finland
Rules for energy calculations, net heating energy demand (net delivered
/ purchased energy)
Ventilation heat losses
•air flow rates and operation time: chapter 3.2 and 3.3
•electricity for fans, pumps etc. are included
•annual energy efficiency of ventilation heat recovery: defrosting,
supply air temp. ratio and ratio between supply and exhaust air are
taken into account
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Heating, ventilation and energy efficiency in Finland
Rules for energy calculations, net heating energy demand (net delivered
/ purchased energy)
Cooling systems
•first is calculated cooling net energy in rooms and spaces and in
ventilation coils by software with max. 1 hour time step (whole year)
•then can be used D5 2012 Chapter 8 method for electricity demand of
cooling and its auxiliary devices
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Heating, ventilation and energy efficiency in Finland
Rules for energy calculations, net heating energy demand (net delivered
/ purchased energy)
Lighting and appliances
•in this used Table 3 and Equation 4 Chapter 3.3.2
•principle is that heat gains / loads are equal to electricity demand and
vice versa
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Heating, ventilation and energy efficiency in Finland
5. Compliance with regulations
For every building is needed to make an Energy Report
•first version in design phase
•updating just before commissioning
Energy Report must include the following initial data:
• calculated E-indicator, max. values in Chapter 2.1.4
• initial data and results of energy calculations
• summertime indoor max. temp. and cooling power if needed
• U-values and areas of building constructions by each orientation
• heating power demand at design conditions
• Energy label of the building
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Heating, ventilation and energy efficiency in Finland
5. Evidence of conformity (with regulations)
To make / produce the Energy Declaration
•requirements for calculation tool / software are that they are validated
•in simplest cases like one family houses and residential buildings (or
others) without cooling / air conditioning calculation can be based on
average monthly values like average outdoor temp. etc. (like D5
method)
•in all other cases a dynamic calculation tool is needed so that storage of
heat / “cool” in constructions is taken into account
•results will be given e.g. like in Table 13...
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