Intelligent ventilation control for optimizing HVAC operations
A method for operating a temperature control system is disclosed. The method includes monitoring an interior and exterior temperature of a structure, defining a first time range and a second time range, associating one or more operating parameters of the temperature control system with the first time range, associating one or more operating parameters of the temperature control system with the second time range, monitoring operational time and operational load of the cooling system for the first time range, predicting a space temperature and an outdoor air temperature for a subsequent time period, and controlling a ventilation subsystem during the second time range based upon the monitored operational time and operational load of the cooling subsystem for the first time range, the predicted space temperature, the predicted outdoor air temperature, and the one or more operating parameters of the cooling subsystem associated with the second time range.
1. A method for operating a temperature control system having a ventilation subsystem for a structure, the method comprising:
monitoring an indoor temperature of a structure;
monitoring an exterior temperature of ambient air outside of the structure;
monitoring operational time and heat transfer metric of a ventilation subsystem;
receiving a predicted outdoor air temperature for a subsequent time period;
controlling the ventilation subsystem during the subsequent time period based upon the monitored operational time and heat transfer metric of the ventilation subsystem, the monitored interior and exterior temperatures, and the predicted outdoor air temperature; and
monitoring an operating status of a ventilation system;
monitoring a supply air temperature and a return air temperature;
monitoring space temperature set points;
calculating a first average space temperature set point for a first time period based upon the monitored inside air temperature;
calculating a second average space temperature set point for a second time period based upon the monitored inside air temperature;
calculating a first average outdoor air temperature for the first time period based upon the monitored outdoor air temperature;
calculating a second average outdoor air temperature for the second time period based upon the monitored outdoor air temperature; and
controlling the temperature control system based upon the supply air temperature, the return air temperature, the monitored space temperature set points; the operating status of the ventilation system, the calculated first average space temperature, the calculated second average space temperature, the calculated first average outdoor air temperature, and the calculated second average outdoor air temperature.
2. The method of claim 1 , wherein the temperature control system further includes an outdoor air damper; and wherein the method further includes:
monitoring a mixed air temperature, wherein the mixed air temperature is monitored within a housing of the temperature control system;
calculating an opening position of the outdoor air damper based upon the monitored return air temperature, the monitored mixed air temperature, and the monitored outdoor temperature;
iteratively, at defined time periods, summing, for a first result, a product of the monitored operating status of the ventilation system with a difference of the supply air temperature and the monitored return air temperature and a difference of a product of the monitored operating status of the ventilation system and the calculated opening position of the outdoor air damper with a difference of the monitored outdoor temperature and the monitored return air temperature;
iteratively, at defined time periods, summing, for a second result, a product of the monitored operating status of the ventilation system and the monitored opening position of the outdoor air damper with a difference of the monitored outdoor temperature and the monitored return air temperature;
determining a variable B, a difference between the first average outdoor air temperature and the first average space temperature subtracted from a product of the sum of the first result and the second result and a variable M calculated by: a difference between the difference of the second average outdoor air temperature for the second time period and the second average space temperature for the second time period and the difference between the first average outdoor air temperature for the first time period and the first average space temperature for the first time period divided by: a difference between the sum of the first result and the second result calculated at the second time period and the sum of the first result and the second result calculated at the first time period; and
further controlling the temperature control system based upon the determined variable B.
3. The method of claim 2 , further comprising:
averaging the variable M over the first time period;
averaging the variable B over the first time period;
dividing the averaging of the variable B by the averaging of the variable M; and
further controlling the temperature control system based upon the dividing.
4. The method of claim 2 , wherein the dividing further comprises estimating of the thermal energy generation by the energy devices within the structure for the second time range.
5. A method for operating a temperature control system for a structure, the method comprising:
monitoring indoor and outdoor temperature;
monitoring an operating state of the temperature control system;
receiving a space temperature set point;
determining a first temperature variable based upon the monitored outdoor air temperature and a correlation of a total heat transferred for the structure and a difference of an average outdoor air temperature and an average space temperature within the structure;
determining a second temperature variable based upon the monitored outdoor air temperature and a correlation of the total heat transferred for the structure and the difference of the average outdoor air temperature and the average space temperature within the structure;
defining a first time range, wherein the first time range comprises a first time period associated with the structure's natural warming, a second time period associated with the structure's natural cooling, and a third time period associated with desirable outside ambient conditions;
wherein an ending time of the second time period and a beginning time of the third time period occurs when the second temperature variable is equal to the space temperature set point;
receiving a predicated outside air temperature for the first time range, the outside air temperature including a low temperature and a time associated with the low temperature;
predicting a space temperature for the first time range;
estimating an operating metric for the temperature control system based upon the (a) monitored interior temperature of the structure, (b) monitored outside air temperature, (c) monitored operating state of the temperature control system, (d) predicted space temperature, and (e) received outdoor air temperature; and
controlling the temperature control system during the third time period based upon the estimated operating metric.
6. The method of claim 5 , wherein the space temperature set point is defined by input received from a user or input received from a temperature schedule.
7. The method of claim 5 , wherein an end time of the first time period and a beginning time of the second time period is determined for t using:
STSP=YODAT1 Ce kt
where
STSP represents the space temperature set point,
k represents a proportionality constant,
YODAT1 represents the outdoor air temperature at a time ‘t’ plus the correlation of the total heat transferred for the structure and the difference of the average outdoor air temperature and the average space temperature within the structure, and
C is a constant.
8. The method of claim 7 , wherein a temperature may be predicted for a time ‘t’ during the first time range using:
∫
t
1
t
2
(
YODAT
1
-
Ce
kt
)
dt
=
∫
t
1
t
2
(
YODAT
1
)
dt
-
∫
t
1
t
2
(
Ce
kt
)
dt
=
(
YODAT
1
)
t
❘
t
1
t
2
-
C
k
(
e
kt
)
❘
t
1
t
2
=
(
YODAT
1
)
(
t
2
-
t
1
)
-
C
k
(
e
k
(
t
2
)
-
e
k
(
t
1
)
)
where t 1 represents a beginning time of the first time period and t 2 represents both an end time of the first time period and a beginning time of the second time period,
k represents a proportionality constant,
YODAT1 represents the outdoor air temperature plus the correlation of the total heat transferred for the structure and the difference of the average outdoor air temperature and the average space temperature within the structure,
C is a constant.
9. The method of claim 8 , wherein a temperature may be predicted for a time ‘t’ during the second time range using:
∫
t
2
t
3
(
STSP
)
dt
=
(
STSP
)
t
❘
t
2
t
3
=
(
STSP
)
(
t
3
)
-
(
STSP
)
(
t
2
)
=
STSP
(
t
3
-
t
2
)
where t 2 represents a beginning time of the second time period and t 3 represents both an end time of the second time period and a beginning time of the third time period,
STSP represents the space temperature set point,
k represents a proportionality constant.
10. The method of claim 9 , wherein a temperature may be predicted for a time ‘t’ during the third time period using:
∫
t
3
t
4
(
Ce
kt
+
YODAT
2
)
dt
=
∫
t
3
t
4
(
Ce
kt
)
dt
+
∫
t
3
t
4
(
YODAT
2
)
dt
=
C
k
(
e
kt
)
❘
t
3
t
4
+
(
YODAT
2
)
t
❘
t
3
t
4
=
C
k
(
e
k
(
t
4
)
-
e
k
(
t
3
)
)
+
(
YODAT
2
)
(
t
4
-
t
3
)
where t 3 represents a beginning time of the third time period and t 4 represents an end time of the third time period,
YODAT2 represents the outdoor air temperature plus the correlation of the total heat transferred for the structure and the difference of the average outdoor air temperature and the average space temperature within the structure,
k represents a proportionality constant, and
C is a constant.
11. A method for predicting a space temperature within a structure, the method comprising:
monitoring indoor temperature;
receiving outdoor temperature;
receive one or more user-supplied temperature set point(s) associated with the one or more prior defined time periods;
correlating received outdoor air temperature to monitored indoor temperature;
determining a rate of change of temperature of the structure with respect to time based upon a proportionality between at the rate of change and a difference in the temperatures of the monitored indoor temperature and the received outdoor temperature;
predicting a space temperature within a structure based upon the determined rate of change and the received one or more user-supplied temperature set point(s); and
controlling the temperature control system based upon the predicted space temperature.