# US 10,481,019 B2 · Method and device for determining the heat loss coefficient of a premises

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- Number: US 10,481,019 B2
- Document ID: US10481019B2
- Status: Granted
- Kind: B2
- Application number: 15/109,063
- Filed: 2014-12-29
- Published: 2016-11-10
- Granted: 2019-11-19
- Earliest claimed: 2013-12-30
- Assignees: Saint-Gobain Isover
- Applicants: Saint-Gobain Isover
- Inventors: Guillaume Pandraud; Florent Alzetto
- Web page: https://patentgrep.com/patent/US10481019B2

## CPC

- G01K 17/20: across a radiating surface, combined with ascertainment of the heat-transmission coefficient
- G01K: MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR (radiation pyrometry G01J5/00)

## Abstract

A method for determining a heat loss coefficient of a premises includes undertaking application of first and second heating powers, respectively, in the premises over two successive time periods, selecting for each of the first and second time periods, a time interval for which the evolution is substantially linear, determining the slope of the tangent to the curve (Tik(t))k=1 or 2 over each time interval; and deducing the value of the heat loss coefficient of the premises on the basis of the slopes.

## Claims

### Claim 1

A method for reducing a value Kcalc of a heat loss coefficient K of a premises, comprising:
undertaking, in the premises, over two successive time periods D1 and D2 :
i. over the first time period D1, an application of a first heating power P1 of the premises, a campaign of measurements of at least one temperature inside the premises Ti1 at closely-spaced time intervals, and a determination of the temperature of an outside air Te1 at closely-spaced time intervals, the first heating power P1 being such that a parameter
α
=
1
-
Δ
⁢
⁢
T
1
⁡
(
0
)
⁢
K
ref
P
1
⁢
is less than or equal to 0.8 with ΔT1(0)=Ti1(t=0)−Tem, where t=0 is a starting point of the first time period D1, Tem is an average temperature of the outside air over all of the time periods D1 and D2 and Kref is a reference value of a heat loss coefficient K of the premises, and then
ii. over the second time period D2, the application of a substantially zero second heating power P2 of the premises, the campaign of measurements of at least one temperature inside the premises Ti2 at closely-spaced time intervals, and the determination of the temperature of the outside air Te2 at closely-spaced time intervals;
selecting for each of the first and second time periods D1 and D2, a time interval Δt1 or Δt2 for which an evolution Ti1(t) or Ti2(t) is substantially linear, where the time intervals Δt1 and Δt2 are such that the time interval Δt1 extends up to an end of the first period D1 of application of the first heating power P1 and such that, when the starting points of the first period D1 and of the second period D2 are superimposed, the time intervals Δt1 and Δt2 have a same end point;
determining a slope a1 or a2 of a tangent to a curve (Tik(t))k=1 or 2 over each time interval Δt1 or Δt2;
determining the value Kcalc of the heat loss coefficient K of the premises based on the slopes a1 and a2;
controlling the error in the value Kcalc of the heat loss coefficient K of the premises by controlling the parameter α less than or equal to 0.8; and
reducing the value Kcalc of the heat loss coefficient K of the premises based on the controlled error, the value Kcalc of the heat loss coefficient K of the premises being greater than or equal to 80% of the heat loss coefficient K of the premises and less than or equal to 120% of the heat loss coefficient K of the premises.

### Claim 2 (depends on 1)

The method as claimed in claim 1, wherein the time intervals Δt1 and Δt2 have a same duration.

### Claim 3 (depends on 1)

The method as claimed in claim 1, wherein the first time period D1, over which the first heating power P1 is applied, has a duration of less than or equal to 4 hours.

### Claim 4 (depends on 1)

The method as claimed in claim 1, wherein the first heating power P1 is such that the parameter
α
=
1
-
Δ
⁢
⁢
T
1
⁡
(
0
)
⁢
K
ref
P
1
⁢
is less than or equal to 0.75.

### Claim 5 (depends on 1)

The method as claimed in claim 1, wherein the first heating power P1 is such that the parameter
α
=
1
-
Δ
⁢
⁢
T
1
⁡
(
0
)
⁢
K
ref
P
1
⁢
is less than or equal to 0.7.

### Claim 6 (depends on 1)

The method as claimed in claim 1, wherein the first heating power P1 is such that the parameter
α
=
1
-
Δ
⁢
⁢
T
1
⁡
(
0
)
⁢
K
ref
P
1
⁢
is greater than or equal to 0.25.

### Claim 7 (depends on 1)

The method as claimed in claim 1, subsequent to the determination of the value Kcalc of the heat loss coefficient K of the premises based on the slopes al and a2, the method further comprising:
computing and verifying a value of the parameter
α
calc
=
1
-
Δ
⁢
⁢
T
1
⁡
(
0
)
⁢
K
calc
P
1
⁢
,
wherein αcalc is in a predefined range of values for the parameter α.

### Claim 8 (depends on 1)

The method as claimed in claim 1, wherein the reference value Kref of the heat loss coefficient K of the premises is determined based on the heat transfer coefficient of an envelope of the premises obtained according to the standard ISO 13789:2007.

### Claim 9 (depends on 1)

The method as claimed in claim 1, wherein the first heating power P1 includes a heating power Pimp1 imposed by a controlled power source.

### Claim 10 (depends on 1)

The method as claimed in claim 1, wherein the method is implemented whilst the premises is unoccupied.

### Claim 11 (depends on 1)

The method as claimed in claim 1, wherein, over each of the first and second time periods D1 and D2, the temperature of the outside air Te1 or Te2 is stable.

### Claim 12 (depends on 1)

The method as claimed in claim 1, wherein, over each of the first and second time periods D1 and D2, a solar radiation is low.

### Claim 13 (depends on 1)

The method as claimed in claim 1, wherein the method is carried out in its entirety over a single nocturnal period.

### Claim 14 (depends on 1)

The method as claimed in claim 1, wherein, over each of the first and second time periods D1 and D2 any fixed ventilation system fitted to the premises is deactivated.

### Claim 15

An information recording medium including instructions for implementation of a method for reducing the heat loss coefficient K of a premises when the instructions are executed by an electronic computation unit, the method comprising:
determining a first heating power P1 to be applied over a first time period D1 based on values of α, ΔT1(0) and Kref, the first heating power P1 being such that a parameter
α
=
1
-
Δ
⁢
⁢
T
1
⁡
(
0
)
⁢
K
ref
P
1
⁢
is less than or equal to 0.8 with ΔT1(0)=Ti1(t=0)−Tem, where t=0 is a starting point of the first time period D1, Tem is an average temperature of the outside air over all of the time periods D1 and D2 and Kref is a reference value of a heat loss coefficient K of the premises;
applying the first heating power P1 of the premises, campaigning measurements of at least one temperature inside the premises Ti1 at closely-spaced time intervals, and determining the temperature of an outside air Te1 at closely-spaced time intervals, over the first time period D1;
determining, over each time interval Δt1 or Δt2, the slope a1 or a2 based on the measurements of the temperature inside the premises Ti1 or Ti2;
applying a substantially zero second heating power P2 of the premises, campaigning measurements of at least one temperature inside the premises Ti2 at closely-spaced time intervals, and determining the temperature of the outside air Te2 at closely-spaced time intervals, over the second time period D2;
selecting for each of the first and second time periods D1 and D2, a time interval Δt1 or Δt2 for which an evolution Ti1(t) or Ti2(t) is substantially linear, the time interval Δt1 extending up to an end of the first period D1 of application of the first heating power P1, and when the starting points of the first period D1 and of the second period D2 are superimposed, the time intervals Δt1 and Δt2 have a same end point;
determining a slope a1 or a2 of a tangent to a curve (Tik(t))k=1 or 2 over each time interval Δt1 or Δt2;
determining the value Kcalc of the heat loss coefficient K of the premises based on the slopes a1 and a2;
controlling the error in the value Kcalc of the heat loss coefficient K of the premises by controlling the parameter α less than or equal to 0.8; and
reducing the value Kcalc of the heat loss coefficient K of the premises based on the controlled error, the value Kcalc of the heat loss coefficient K of the premises being greater than or equal to 80% of the heat loss coefficient K of the premises and less than or equal to 120% of the heat loss coefficient K of the premises.

### Claim 16 (depends on 15)

The information recording medium as claimed in claim 15, further comprising controlling, as a function of input data, a controlled power source used to apply the first heating power P1 in the premises.

### Claim 17

A device for reducing a value Kcalc of a heat loss coefficient K of a premises, the device comprising:
at least one heating element including a controlled power source;
at least one temperature sensor measuring temperature inside the premises Tik and temperature of outside air Tek;
at least one power sensor measuring a heating power Pk delivered in the premises; and
Tik Pk Tek
processing circuitry configured to
determine a first heating power P1 to be applied over a first time period D1, based on values of α, ΔT1(0) and Kref, over the first time period D1, by applying the first heating power P1 of the premises, campaigning of measurements of at least one temperature inside the premises Ti1 at closely-spaced time intervals, and determining the temperature of the outside air Te1 at closely-spaced time intervals, the first heating power P1 being such that a parameter
α
=
1
-
Δ
⁢
⁢
T
1
⁡
(
0
)
⁢
K
ref
P
1
⁢
is less than or equal to 0.8 with ΔT1(0)=Ti1(t=0)−Tem, where t=0 is a starting point of the first time period D1, Tem is an average temperature of the outside air over all of the time periods, and Kref is a reference value of a heat loss coefficient K of the premises,
determine, over each time interval Δt1 or Δt2, a slope a1 or a2 based on the measurements of the temperature inside the premises Ti1 or Ti2, over a second time period D2, by applying a substantially zero second heating power P2 of the premises, campaigning measurements of at least one temperature inside the premises Ti2 at closely-spaced time intervals, and determining the temperature of the outside air Te2 at closely-spaced time intervals,
determine the value Kcalc of the heat loss coefficient K of the premises based on the slopes a1 and a2,
control the error in the value Kcalc of the heat loss coefficient K of the premises by controlling the parameter α less than or equal to 0.8, and
reduce the value Kcalc of the heat loss coefficient K of the premises based on the controlled error, the value Kcalc of the heat loss coefficient K of the premises being greater than or equal to 80% of the heat loss coefficient K of the premises and less than or equal to 120% of the heat loss coefficient K of the premises.

### Claim 18 (depends on 17)

The device as claimed in claim 17, wherein the at least one heating element heats the air of the premises.

### Claim 19 (depends on 17)

The device as claimed in claim 17, wherein the at least one temperature sensor measures the temperature of air inside the premises.

### Claim 20 (depends on 17)

The device as claimed in claim 17, wherein the processing circuitry is further configured to control the power source of the at least one heating element.

### Claim 21 (depends on 17)

The device as claimed in claim 17, further comprising at least one box located in a room or zone of the premises,
wherein the at least one box includes the at least one power sensor measuring the heating power delivered in the room or zone of the premise, the at least one power sensor being connected to the at least one temperature sensor located in said room or zone of the premises, and
wherein the processing circuitry connected to the at least one box is further configured to receive the measurements of the temperature and of the heating power, and to control the heating power in the room or zone of the premise.

### Claim 22 (depends on 21)

The device as claimed in claim 21, wherein the at least one box further includes a box in each room or zone of the premises.

### Claim 23 (depends on 21)

The device as claimed in claim 21, the at least one box and the processing circuitry are connected by wireless connection.