Constructions (transparant)

Frame data

Frame

The frame is the part of the total window area that contains a frame, expressed in frame percentage (%) or frame thickness (mm).

• The frame percentage (default 5%) is the percentage of frame area relative to the total window area;
• The frame thickness (default 67 mm), or frame width of the window frame, is the gross width of the frame edge. Based on this input width, Vabi Elements calculates the frame area considering a single frame around the window. Transoms and mullions are therefore not included in the calculation. If transoms and mullions need to be included in the calculation, we recommend manually calculating the frame percentage.

 

Houses
Window area [m²]	Glass percentage [%]
	Metal frame	Wooden or plastic frame
0,5	70	65
0,75	75	70
1,0	80	85
1,5	84	89
2,0	86	90
2,5	87,5	92
3 and bigger	88,5	93
Utilitity
Window area [m²]	Glass percentage [%]
With opening windows	70
Without opening windows	85

 

Publications

 

Frame type

Here you define a U-value of a window frame based on a selected standard window type according to ISSO 8, table 7. If you know the U-value yourself, you can enter it directly.

Frame type	U-value frame (W/m².K)
Wood	2,4
Plastic	2,0
Metal	5,9
Metal with thermal barrier	3,8

 

U-value frame

This is the heat transfer coefficient (U-value) of the window frame. A well-insulated frame has the lowest possible U-value.

Ψ-value

The PSI-value is the linear thermal bridge between the glass and the frame. This linear thermal bridge is calculated around the perimeter of the glass, which is the perimeter of the window minus the thickness of the frame. A well-insulated frame has the lowest possible PSI-value.

Publications

 

Absorption

Absorption is the heat or cold that a surface of a construction can absorb relative to its specific heat capacity. This property depends, for example, on the surface finish such as color and coating, and the type of material. Absorption applies to shortwave solar radiation. Emission concerns longwave radiation. Therefore, absorption and emission do not need to be equal. Metal surfaces generally have a lower value.

Emission

Emission is the heat or cold that a surface of a construction can emit to its surroundings relative to its specific heat capacity. This property depends, for example, on the type of material. Emission concerns longwave radiation. Absorption applies to shortwave solar radiation. Therefore, these do not need to be equal.

Glass data

Glass type

This choice includes preset glass data such as U-value (Ug), solar heat gain coefficient (g-value), absorption, transmittance, LTA (Light Transmittance and Absorbance), and reflection for commonly used glazing types. If you have specific glass data, you can enter your own values. Make sure to enter factors rather than percentages in Vabi Elements.

 

Publications

 

U

The U-value (Ug) is the heat transfer coefficient of the glass. It represents the rate of heat transfer in Watts per unit area per degree Kelvin temperature difference between the inside and outside of the glass. This thermal property should be measured perpendicular to the surface, according to NEN-EN 673:2011. Well-insulated glass has the lowest possible U-value.

g-value (ggl;n) 

The solar heat gain coefficient (g-value or g-factor) is the solar factor and indicates the ratio between the incoming and incident solar radiation. It is a product characteristic of a glass system and measures the total amount of solar energy transmitted through the glass system in the form of shortwave radiation, longwave radiation, and convective heat transfer. The value ranges between 0 and 1. A higher g-value means more heat enters the building.

This glass property should be measured according to NEN-EN 410:2011, and it represents solar transmittance under perpendicular incidence.

Transmission energy

This is the direct energy transmission [αe, TE%] and indicates the percentage of energy that passes through the glass. It represents the portion of directly transmitted solar energy, in other words, transmitted solar radiation compared to the total incident solar radiation. The higher the τe value, the more light is transmitted. This glass property should be measured according to NEN-EN 410:2011.

Absorption energy

Energy absorption [αe, AE1% + AE2%] is the portion of solar energy absorbed by the glass. This glass property should be measured according to NEN-EN 410:2011. The higher the absorption, the more energy is absorbed.

Reflection energy

Energy reflection is the percentage of energy that is reflected by the glass. The higher the reflection, the more energy is reflected.

Transmission light (LTA)

This is the light transmittance factor [τv, TL%], also known as light transmission, which indicates the ratio of incoming visible solar radiation to the incident visible solar radiation at a perpendicular angle. This coefficient is used to determine the light entering a space and is used for controlling lighting. The higher the LTA value, the more visible light and heat enter. This glass property should be measured according to NEN-EN 410:2011.

Reflection light

Visible reflectance [ρv, RLe%], or visible light reflectance, indicates the percentage of visible light that is reflected by the glass. The higher the reflectance, the more light is reflected. This glass property should be measured according to NEN-EN 410:2011.

Absorption light

Light absorption is the portion of light absorbed by the glass. The higher the absorption, the more light is absorbed.

Climate window

Ventilation

Fill in how the ventilation in the climate window takes place. A climate window is ventilated and this can be done in various ways. It is assumed here that there is complete extraction at the window, because the window is part of the Mechanical Ventilation and Heat Recovery System (MVHR).

Fill in how the ventilation in the climate window takes place. A climate window is ventilated and this can be done in various ways. It is assumed here that there is complete extraction at the window, because the window is part of the Mechanical Ventilation and Heat Recovery System (MVHR).

Ventilation

Fill in whether the climate window is ventilated.

Ventilation from

Source of ventilation air:

• Outside air: the air is supplied from outside.
• Inside air: the air is supplied from inside.

Ventilation to

Where the ventilation air is exhausted:

• Outside air: the air is exhausted to the outside.
• Inside air: the air is exhausted to the inside.
• System: the air is extracted by a local system.

Blinds

Movable blinds

Here you choose whether to install controlled sun shading at the window. When you check the box for sun shading, all subsequent settings will appear. This setting applies regardless of whether it concerns a standard window or a climate window.

For the placement, you have the following options:

• External blinds: External sun shading installed outside the window, such as screens.
• Blinds between panes: Sun shading installed inside or between the window, such as blinds.
• Internal blinds: Sun shading installed on the inside of the window.

For sun shading, the most important factor is the transmission of energy, or transmittance. In good sun shading, this value will be low, whereas in poor sun shading, it will be high. There is also a difference between indoor and outdoor sun shading.

For indoor sun shading, the level of reflection is crucial. A higher reflection reduces the transmission of energy. High absorption is not desirable for indoor sun shading because it creates large radiant surfaces.

In contrast, absorption is less critical for outdoor sun shading because absorbed heat does not radiate indoors. Therefore, the absorption value can be higher for outdoor sun shading compared to indoor, where a high absorption is undesirable.

Publications

 

Control

The control provides an option for how the sun shading is regulated. You can then define this choice under the sun shading switching level in the building template building controls.

• Manual: The sun shading is manually controlled. Depending on the setting under Building Controls, it can either be continuously open, continuously closed, or controlled via a specific switching level.
• Automatic: The sun shading is automatically controlled. Depending on the setting under Building Controls, it can either be continuously open, continuously closed, or controlled via a specific switching level.

Type

Fill in the type of sun protection here. There is a difference between indoor and outdoor/ between sun protection. You can choose from the following types:

External blinds and blinds between panes

Energy	Good	Moderate	Bad
Transmission ts	0.03	0.12	0.19
Absorption as	0.92	0.43	0.14
Reflection rs	0.05	0.45	0.67
Licht
Transmission (LTA) tv	0.03	0.11	0.19
Reflection rv	0.05	0.48	0.76
Absorption av	0.92	0.41	0.05

 

Internal blinds

Energie	Goed	Matig	Slecht
Doorlating	0.05	0.05	0.10
Absorptie	0.20	0.52	0.81
Reflectie	0.75	0.43	0.09
Licht
Doorlating (LTA)	0.06	0.04	0.10
Reflectie	0.74	0.42	0.09
Absorptie	0.20	0.54	0.81

Creation of blind values

Type of blinds: User defined

Voor zonwering kan je Eigen waarden voor de doorlating, absorptie en reflectie voor energie en zichtbare licht invullen. In onderstaande tabel geven we aan hoe je de Fc waardes van de NTA8800 in kan vullen in Elements. Deze waarden kunnen ook als leidraad dienen voor als je het type zonwering weet, maar niet welke doorlating, absorptie en reflectie waardes hierbij horen.

For blinds, you can enter your own values for transmission, absorption, and reflection for energy and visible light. In the table below, we indicate how to fill in the Fc values from the NTA8800 in Elements. These values can also serve as a guideline if you know the type of sun protection but not the corresponding transmission, absorption, and reflection values.

FC value

The FC value is a combination of the properties of the window and the properties of the blinds. The FC value from Vabi EPA is equal to the g-value of the composite glass with sun protection divided by the g-value of the glass alone (see also NTA 8800 – formula 7.43).

In the table below, you can find what you can enter in Vabi Elements for HR++ glass to achieve the correct FC value.

Type of blinds	Color	criteria		Fc	Energy			Light			G glass	G tot	Fc
		Ts	Rs		D	A	R	D	A	R
Screens	zwart	<0.07		0.12	0.10	0.88	0.02	0.03	0.92	0.05	0.58	0.071	0.12
	overig	<0.17		0.20	0.17	0.38	0.45	0.11	0.41	0.48	0.58	0.117	0.20
	wit	>=0.17		0.25	0.21	0.12	0.67	0.19	0.05	0.76	0.58	0.147	0.25
Blinds	zwart		<0.3	0.05	0.03	0.92	0.05	0.03	0.92	0.05	0.58	0.03	0.05
	overig		<0.6	0.10	0.08	0.43	0.49	0.11	0.41	0.48	0.58	0.059	0.10
	wit		>=0,6	0.20	0.16	0.14	0.7	0.19	0.05	0.76	0.58	0.114	0.20
Roller shutters	overig		<0.70	0.11	0.09	0.43	0.48	0.11	0.41	0.48	0.58	0.065	0.11
	wit		>0.70	0.04	0.03	0.20	0.76	0.19	0.05	0.76	0.58	0.024	0.04
Metallized fabrics, indoor			>0.72	0.45	0.05	0.13	0.82	0.06	0.20	0.74	0.58	0.263	0.45
Drop arm awnings				0.35	0.30	0.14	0.56	0.19	0.05	0.76	0.58	0.204	0.35
				0.45	0.39	0.14	0.47	0.19	0.05	0.76	0.58	0.259	0.45
				0.50	0.44	0.14	0.42	0.19	0.05	0.76	0.58	0.288	0.50
				0.55	0.49	0.14	0.37	0.19	0.05	0.76	0.58	0.317	0.55
				0.65	0.60	0.14	0.26	0.19	0.05	0.76	0.58	0.377	0.60
				0.80	0.77	0.14	0.09	0.19	0.05	0.76	0.58	0.464	0.80
				0.90	0.88	0.10	0.02	0.19	0.05	0.76	0.58	0.521	0.90

See also NTA 8800 – Table 7.5 Forfait values for the reduction factor for the total solar transmittance factor, for screens, blinds, and metallized fabrics.

Convective factor artificial lighting

When internal blinds are present, the convective factor artificial lighting can be filled in. The heat radiation from the artificial lighting causes the indoor sun protection to warm up and radiate heat. The impact of the convective factor also depends on the specified lighting power.

Fixed outdoor blinds

Fixed external blinds is an option that can only be applied for an EPG calculation. It concerns external sun protection that is always present. For fixed blinds (as well as for diffusing glazing), the time-averaged solar heat gain factor \( g_{gl} \) is used, which is calculated from the specified g-value at a solar altitude of 45º and the g-value for isotropic diffuse solar radiation.

Dispersive glazing

Dispersive glazing is an option that can only be applied for an EPG calculation. For dispersive glazing, the time-averaged solar heat gain factor \( g_{gl} \) is used, which is calculated from the specified g-value at a solar altitude of 45º and the g-value for isotropic diffuse solar radiation.

Solar factor. g (45º)

The g-value of the glass is determined at a solar altitude of 45º. This value can be specified if fixed external blinds or diffusing glazing is chosen, and it is used for the calculation of the \( g_{gl} \) value.

Solar factor. g (isotropic diffuse)

The g-value for isotropic diffuse solar radiation is determined according to ISO 15099. This value can be specified if fixed external sun protection or diffusing glazing is chosen, and it is used for the calculation of the \( g_{gl} \) value.

Publication

Dutch climate facade

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