Device for measuring the perceived temperature

1. A sensor (S) for measuring a perceived temperature of an environment comprising:

at least one first sensitive element ( 1 ), configured to be exposed to the environment for which the perceived temperature is to be estimated, configured to be supplied with a variable power, so as to dissipate a thermal power equal to the power that would be dissipated by conduction, convection and radiation from any portion of human skin exposed to the same environment;

a device for measuring a temperature of said first sensitive element ( 1 ),

a microcontroller ( 8 ),

electrical supply means controlled by said microcontroller ( 8 ) and adapted to supply said first sensitive element ( 1 ) with an electrical power determined by said microcontroller ( 8 );

at least one second sensitive element ( 3 ), configured to measure a temperature (T amb ) and relative humidity (UR a ) of the ambient air,

said sensor (S) is characterized by:

said first sensitive element ( 1 ) consists of a thermo-resistance having a thin planar shape and configured to measure its own temperature by means of its Temperature Coefficient of Resistance (TCR);

and wherein:

said thermo-resistance consists of a metal element having a TCR greater or equal to a TCR of a metal element made of platinum

and

said thermo-resistance has any two sides directly facing the external environment;

and wherein said first sensitive element ( 1 ) is provided with a mechanical protection adapted to allow air to flow freely and not to significantly obstruct an angle subtended by the sensor (S) and wherein an electrostatic potential is applied to said mechanical protection so that it acts as an electrostatic protection system against dust.

2. The sensor (S) for measuring a perceived temperature of an environment according to claim 1 , further comprising a selector ( 12 ) for selecting a value of metabolic activity (MET) for which to measure the perceived temperature and provides a customization of the metabolic rate.

3. The sensor (S) for measuring a perceived temperature of an environment according to claim 1 , wherein said first sensitive element ( 1 ) has a surface/volume ratio in the range of 10 to 50 mm.

4. The sensor (S) for measuring a perceived temperature of an environment according to claim 1 , wherein said first sensitive element ( 1 ) has a resistance value in the range of 1 to 100 ohms.

5. The sensor (S) for measuring a perceived temperature of an environment according to claim 1 , wherein said first sensitive element ( 1 ) consists of a double polygonal spiral winding of a small section metal wire with a diameter between 0.10 and 0.05 mm.

6. The sensor (S) for measuring a perceived temperature of an environment according to claim 1 , wherein said first sensitive element ( 1 ) is made from thin metal sheet with a thickness between 0.10 and 0.05 mm laser cut or sheared according to interdigital geometries to obtain a track conformation developed according to a serpentine-shape inside an insulating frame.

7. The sensor (S) for measuring a perceived temperature of an environment according to claim 1 , wherein said first sensitive element ( 1 ) is integrated in a microelectronic system able to carry out all or part of the processing, using wire-bonding.

8. The sensor (S) for measuring the perceived temperature of an environment according to claim 1 , wherein said electrical supply of the first sensitive element ( 1 ) is configured to provide a PWM (Pulse Width Modulation) technique to provide the first sensitive element ( 1 ) for a short period of time with a higher power than a required one, then repeating the operation after a period of time such that the mean power value is exactly the required one.

9. The sensor (S) for measuring the perceived temperature of an environment according to claim 1 , wherein said microcontroller ( 8 ) is configured to carry out a closed-loop control based on the measurement of the temperature derivative of said first sensitive element ( 1 ) in order to accelerate thermal regulation.

10. The sensor (S) for measuring the perceived temperature of an environment according to claim 1 , wherein said mechanical protection is configured to act as a casing for the entire sensor (S) so as to allow connection of the device to a power outlet or to a lamp holder.

11. The sensor (S) for measuring the perceived temperature of an environment according to claim 1 , wherein said mechanical protection is also configured to make the device able to interact with equipment and machines for the thermoregulation of environments in an integrated mode or remotely by using wireless and/or Bluetooth protocols.

12. The sensor (S) for measuring the perceived temperature of an environment according to claim 1 , further comprising a third sensitive element ( 2 ) mounted-inside a casing, configured so that said third sensitive element ( 2 ) is exposed to an additional environment having a temperature equal to that of the environment for which the perceived temperature is to be measured.

13. A method for measuring the perceived temperature of an ambient environment by means of a device according to claim 1 , comprising the steps of:

( 10 ) Measuring the ambient air temperature (T amb ) and the relative ambient humidity (UR a ) by means of the said second sensitive element ( 3 );

( 20 ) Estimating the total specific power (Q a ) dissipated by the skin as a function of the metabolic activity and as a function of the value set by a personalization capability

( 30 ) Estimating the specific power dissipated by the skin by evaporation/perspiration (Q trp ) as a function of:

the ambient temperature (T amb ) measured at point ( 10 ),

the relative ambient humidity (UR a ) measured in point ( 10 ),

the temperature (T s ) of said first sensitive element ( 1 );

( 40 ) Powering said first sensitive element ( 1 ) with a specific power equal to the difference between said specific powers (Q a , Q trp ) calculated at points ( 10 ) and ( 20 );

( 50 ) Measuring the temperature (T s (i)) of said first sensitive element ( 1 );

( 60 ) Updating the estimate of said specific power dissipated through the skin by evaporation/perspiration (Q trp ) as a function of:

the ambient temperature (T amb ) measured at point ( 10 ),

the relative ambient humidity (UR a ) measured at point ( 10 ),

the temperature (T s (i)) of said sensitive element ( 1 ) measured at point ( 50 ),

( 70 ) Repeating steps ( 40 ) to ( 60 ) until the convergence of the value of said temperature (T s (i)) of said first sensitive element ( 1 ), thus determining the temperature of the skin (T skin =T s (i));

( 80 ) Estimating the specific power exchanged for evaporation/perspiration from the skin exposed to the reference environment (Q trp2 ) as a function of:

the ambient temperature (T amb ) measured at point ( 10 ),

the relative humidity assumed equal to 50%;

a skin temperature (T skin ) determined at point ( 70 ),

( 90 ) Determining the specific power (P 2 ) that would be dissipated in the reference environment by conduction, convection and irradiation as the difference between the specific powers (Q a , Q trp2 ) estimated at points ( 20 ) and ( 80 ),

( 100 ) Estimating the value of the perceived temperature (T p ) as a function of the specific power (P2) calculated at point ( 90 ) and of said skin temperature (T skin ) calculated at point ( 70 ).

14. The method according to claim 13 wherein said estimate of the value of the perceived temperature (T p ) estimated at point ( 100 ) is calculated by obtaining the value of the perceived temperature (T p ) by interpolation in a two-input data table, stored in said microcontroller ( 8 ), which contains the values of the perceived temperature (T p ), corresponding to various values of the specific power (P 2 ) that would be dissipated by conduction, convection or radiation in the reference environment, and of the temperature of the skin (T skin ).

15. The method according to claim 14 wherein said sensor (S) further comprises a third sensitive element ( 2 ), constructed in the same manner as said first sensitive element ( 1 ) and located inside a casing configured to expose said third sensitive element ( 2 ) to an environment having a temperature equal to the room temperature, walls isothermal with air and zero air velocity

in that

said third sensitive element ( 2 ) is supplied with said specific power (P 2 )

calculated at point ( 90 )

and wherein

said perceived temperature (T p ) is estimated through the relationship

T

p

=

T

s

⁢

1

-

P

1

P

2

⁢

(

T

s

⁢

2

-

T

a

⁢

i

⁢

r

)

.

16. A device comprising the sensor (S) according to claim 1 and comprising a plurality of “slave” sensors (S s ), each comprising only the first sensitive element ( 1 ), wherein said slave sensor (Ss) is configured to supply local temperatures by delegating the measurement of ambient temperature and humidity to the sensor (S), which carries out an average of perceived temperatures as estimated by the slave sensors (S s ) and configured to provide a mediated value in output.