US2019078799A1PendingUtilityA1
Method and device for determining the air change rate of a room or building
Est. expiryMar 18, 2036(~9.6 yrs left)· nominal 20-yr term from priority
F24F 11/0001F24F 11/62F24F 2110/40F24F 2130/20F24F 2110/20F24F 11/30F24F 2110/65F24F 2110/50F24F 2110/10G06F 30/23F24F 11/63F24F 11/58F24F 11/52Y02B30/70
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Claims
Abstract
A method, which seeks to determine the air change rate of a space, includes, over at least two successive time periods corresponding to distinct given-gas flow rates applied in the space, carrying out a campaign of measurements to determine the concentration of the gas inside the space at closely-spaced time intervals, and the concentration of the gas outside the space is determined at closely-spaced time intervals. The value of the air change rate of the space is determined by causing the convergence of a diffusive model expressing the temporal variation of the concentration of the gas inside the space as a function of the concentration of the gas outside the space and of physical parameters of the space from which parameters the air change rate of the space can be calculated, and the measured change in the concentration of the gas inside the space as a function of time.
Claims
exact text as granted — not AI-modified1 . A method for determining an air change rate ACH of a space, comprising:
carrying out, over at least two successive time periods D k corresponding to distinct given-gas flow rates {dot over (q)} k applied in the space, a campaign of measurements is carried out to make it possible to determine a concentration of the gas inside the space c ik at closely-spaced time intervals, and a concentration of the gas outside the space c ek is determined at closely-spaced time intervals; and determining a value of the air change rate ACH of the space by causing a convergence of:
a diffusive model expressing a temporal variation of the concentration of the gas inside the space c ik as a function of the concentration of the gas outside the space c ek and of physical parameters of the space from which parameters the air change rate ACH of the space can be calculated, and
the measured change c ik (t) in the concentration of the gas inside the space c ik as a function of time.
2 . The method as claimed in claim 1 , wherein:
for each time period D k starting from the measured change c ik (t) in the concentration of the gas inside the space c ik as a function of time:
either, if there is a time interval Δt k for which the change c ik (t) is substantially linear, the gradient a k of the tangent at the change c ik (t) is determined over this time interval Δt k and the value of the air change rate ACH of the space is deduced from the gradients a k ;
or, if there is no time interval for which the change c ik (t) is substantially linear, a time interval Δt k ′ in which the change c ik (t) is substantially exponential of the type exp(−t/τ) is selected, where τ is the time at the end of which the volume of air inside the space has been changed, and the value of the air change rate ACH of the space is deduced, this being the value such that the change
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.
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is a straight line, where θ k (t)=c ik (t)−c ekm ′, where c ekm ′ is the mean of the concentration of the gas outside the space e ek over the time interval Δt k ′.
3 . The method as claimed in claim 1 , wherein the method is implemented with two successive time periods D 1 and D 2 corresponding to two distinct gas flow rate setpoints {dot over (q)} 1 and {dot over (q)} 2 applied in the space.
4 . The method as claimed in claim 1 , wherein the gas is H 2 O, CO 2 , He, SF 6 , H 2 , N 2 or a refrigerant gas.
5 . The method as claimed in claim 1 , wherein, for each time period D k , the gas flow rate {dot over (q)} k applied in the space comprises a flow rate {dot over (q)} impk imposed by means of at least one controlled-flow rate apparatus.
6 . The method as claimed in claim 1 , wherein the measurements making it possible to determine the concentration of the gas inside the space c ik are taken using one or more sensors of said gas which are placed in the interior volume of the space.
7 . The method as claimed in claim 1 , wherein, over each time period D k , the temperature inside the space T ik is stable.
8 . The method as claimed in claim 1 , wherein, over each time period D k , the concentration of the gas outside the space c ek is stable.
9 . The method as claimed in claim 1 , wherein, over each time period D k , the solar radiation is low.
10 . The method as claimed in claim 1 , wherein the method is implemented while the space is unoccupied.
11 . The method as claimed in claim 1 , further comprising verifying that a value V calc of an effective volume of the space, calculated from the diffusive model and from the measured change c ik (t), corresponds to an actual volume of the space.
12 . The method as claimed in claim 1 , wherein:
the carrying out includes, over two successive time periods D 1 and D 2 :
i. over the first time period D 1 , a first gas flow rate {dot over (q)} 1 is applied in the space, and a campaign of measurements is carried out to determine the concentration of the gas inside the space c i1 at closely-spaced time intervals, and the concentration of the gas outside the space c e1 is determined at closely-spaced time intervals, the first gas flow rate {dot over (q)} 1 being such that the parameter
α
=
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-
ACH
ref
Δ
c
1
(
0
)
q
.
1
is less than or equal to 0.8, with Δc 1 (0)=c i1 (0)−c em , where t=0 is the starting point for the first time period D 1 , c em is the mean concentration of the gas outside the space over all the time periods D 1 and D 2 , and ACH ref is a reference value for the air change rate of the space, then
ii. over the second time period D 2 , a substantially zero second gas flow rate {dot over (q)} 2 is applied in the space, and a campaign of measurements is carried out to determine the concentration of the gas inside the space c i2 at closely-spaced time intervals, and the concentration of the gas outside the space c e2 is determined at closely-spaced time intervals.
13 . The method as claimed in claim 1 , wherein the diffusive model is an R-C model.
14 . The method as claimed in claim 1 , wherein the diffusive model is a parametric identification model.
15 . (canceled)
16 . A non-transitory computer-readable recording medium on which is recorded a computer program that, when executed by a computer, causes the computer to execute the method as claimed in claim 1 .
17 . A device for determining an air change rate ACH of a space, comprising:
at least one apparatus configured to apply, over at least two successive time periods D k , distinct given-gas flow rates {dot over (q)} k in the space; at least one sensor configured to measure a concentration of the gas inside the space c ik at closely-spaced time intervals; and a terminal comprising a processing module configured to cause convergence of, a diffusive model expressing a temporal variation of the concentration of the gas inside the space c ik as a function of a concentration of the gas outside the space c ek and of physical parameters of the space from which parameters the air change rate ACH of the space can be calculated, and the measured change c ik (t) in the concentration of the gas inside the space c ik as a function of time, so as to obtain a value of the air change rate of the space.
18 . The device as claimed in claim 17 , further comprising at least one sensor configured to measure the concentration of the gas outside the space c ek at closely-spaced time intervals.
19 . The device as claimed in claim 17 , further comprising at least one temperature sensor configured to measure a temperature inside the space T ik .
20 . The device as claimed in claim 17 , further comprising means of connection between the at least one sensor and the terminal.
21 . The device as claimed in claim 17 , wherein the terminal comprises means of controlling the at least one apparatus configured to apply distinct given-gas flow rates {dot over (q)} k in the space.
22 . A terminal, comprising:
a processing module configured to cause convergence of a diffusive model expressing a temporal variation of a concentration of a given gas inside a space c ik as a function of a concentration of the gas outside the space c ek and of physical parameters of the space from which parameters an air change rate ACH of the space can be calculated, and on the other hand, a measured change c ik (t) in the concentration of the gas inside the space c ik as a function of time, so as to obtain a value of the air change rate of the space.
23 . The terminal as claimed in claim 22 , wherein the processing module comprises a computer program recorded on a recording medium comprising a rewritable nonvolatile memory of the terminal, instructions of said program being interpretable by a processor of the terminal.
24 . The method as claimed in claim 9 , wherein the solar radiation is zero.Join the waitlist — get patent alerts
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