With this app you can calculate the heat transfer coefficient and the energy cost due to the losses of fixtures.

The heat transfer coefficient is the average heat flux which pass through a specific surface when there is a gradient of temperature, knowing the value of the heat transfer coefficient and the difference of temperature is possible to calculate the energy cost.

Frame data

Frame parameters.

Selection of the material

Specific heat transfer coefficient

**W/m ^{2}K**

External visible width of the frame

in meters.

in meters.

External visible height of the frame

in meters.

in meters.

External dimension of the frame

**W _{1} (m)**

**H _{1} (m)**

Parameters for glass and panels.

Selection type of panel

Heat transfer coefficient for the panel or glass.

Linear heat transfer coefficient of the

gap (only for multiple glass).

gap (only for multiple glass).

Specific heat transfer coefficient

**W/m ^{2}K**

**W/m K**

Width of the panel

or glass in meters.

or glass in meters.

Height of the panel

or glass in meters.

or glass in meters.

Dimension of the panel

**W (m)**

**H (m)**

Number of equal panels

**n.**

Add a new panel

Delete last panel

Parameters for calculation of dispersions.

External temperature:

°C

Inner temperature:

°C

Results |
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Total surface | m^{2} |
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Area defined as frame | m^{2} |
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Area defined as panel | m^{2} |
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Heat transfer coefficient | W/m^{2}K |
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Thermal power lost at the setted temperature | kWh | ||

Thermal power lost (equivalent) at the setted temperature | kcal | ||

Hourly consumption of methane of the frame at the setted temperature (normal cubic meter hour) | Nm^{3}/h |

**How much energy does this frame loose ?**

If you already done the calculation, you can calculate how much does the door or the window cost annually
with the characteristics that you have defined using the simple extra calculation below.

Annual cost with electric heating or electric air conditioning:

Cost = **cost_kw x kWh x hours_day x days_month x months_year**

Annual cost with heating using methane:

Cost = **cost_m ^{3} x Nm^{3}/h x hours_day x days_month x months_year**

Values **cost_kw** and **cost_m ^{3}** must be read
on the bill.

The hours per day, the days per month and months per year must be those when the temperatures are on average those setted.

**Practical example with heating using methane:**

- External door in softwood of 50mm, dimensions 0.8m x 2.1m
- 3 double glass (4-12-4), dimensions 0.18m x 1.6m
- Average temperatures = external -8°C, inner 21°C
- Methane cost per m
^{3}=**0.88 Euro al m**^{3} - Hourly cost =
**0.0157 m**^{3}/h - Calculation :
**0.88 x 0.0157 x 10 x 30 x 4 = almost 17 Euro per year.**

**Notes:**

The values in the list for linear heat transfer coefficient of the gaps for glass are
average values, there are of different kind, you can insert also the value manually.

The temperature scales are wider than necessary for calculate industrial application as ovens, refrigerators or climatic chambers in general.

The calculation method can be extended in agreement with the basic norm: UNI EN 10077-1

Instructions

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Notices