Relation between temperature loss rate and U value (transmittance)

Additionally, using the average temperature difference may not be a accurate approximation for your problem as the temperature difference between outside and inside is not constant throughout the day. In summary, the speaker is monitoring a building with temperature sensors and has observed that when the average temperature difference from inside to outside is 9.4K, the inside temperature decreases at a rate of 0.16 K/hour. They are wondering if it is possible to calculate the U value of the building with the data they have and if using the average temperature difference is a good approximation for their problem. However, the U value cannot be determined from the temperature difference alone and using the average temperature difference may not be accurate due to fluctuations throughout the day.
  • #1
DavideF
1
0
I am monitoring a building with temperature sensors.
Observing the inside and outside temperatures I see that when the average temperature difference from inside to outside is 9.4K the speed at which the inside temperature decreases is 0.16 K/hour.

I would like to know if it is possible, with the data I've got, to calculate the U value (W/m2K) of the building so that I can understand its performance and compare it with other buildings.

Since the temperature difference between outside and inside is not constant during the day I am also wondering if using the average temperature difference is a good approximation for my problem.

Thanks
 
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  • #2
for your help.Unfortunately, it is not possible to calculate the U value (W/m2K) of the building from the data you have given. The U value is a measure of the rate at which heat is transferred through a material or structure and cannot be determined from the temperature difference alone. To calculate the U value, you would need information such as the type of material used in the building, the thickness of that material, and the thermal conductivity of the material.
 

1. What is the relationship between temperature loss rate and U value (transmittance)?

The U value, also known as thermal transmittance, represents the rate at which heat is transferred through a material. This means that a lower U value indicates a slower rate of heat loss or gain, while a higher U value means a faster rate of heat transfer. Therefore, there is an inverse relationship between temperature loss rate and U value - as the U value decreases, the temperature loss rate also decreases.

2. How does the U value affect the energy efficiency of a building?

The U value plays a crucial role in determining the energy efficiency of a building. A lower U value means that less heat is able to escape through the building's walls, windows, and roof, resulting in lower energy consumption and cost. In other words, a lower U value translates to a more energy-efficient building.

3. What factors can affect the U value of a material?

The U value of a material is influenced by several factors, including the type and thickness of the material, the presence of insulation, and the number of layers or glazing used. The shape and size of the building, as well as its location and climate, can also impact the U value.

4. Is there a recommended U value for buildings?

The recommended U value for buildings depends on various factors such as the location, climate, and building type. In general, a lower U value is preferred for better energy efficiency. In the United States, the Department of Energy recommends a U value of 0.35 or lower for new windows in most regions.

5. How can the U value be improved?

There are several ways to improve the U value of a building, such as adding insulation, using energy-efficient materials, and reducing air leakage. Double or triple glazing windows, using low-emissivity coatings, and installing thermal breaks can also help improve the U value of a building. It is important to consult with a professional to determine the most effective strategies for improving the U value in a specific building.

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