CONTROL FOR AIR HANDLER
The present invention provides for a control for activating and deactivating heating, cooling and fan recirculate modes having an interval timer switchable between a timer on (TON) state and a timer off (TOFF) state, both the TON and TOFF state durations are variable according to comparisons between room temperature and a set point temperature of the control and the control activating the fan recirculate mode when the room temperature deviates from the set point temperature of the control. An interval spacer is provided to prevent back to back fan on states.
The present application claims priority to provisional Application No. 61/414,260 filed Nov. 16, 2010.
FIELD OF THE INVENTIONThe present invention pertains to a control for an air handler and may comprise a portion of a thermostat. In an embodiment, the control is for an HVAC system and is used to monitor room temperature, allow for programming of desired functions and controlling heating, cooling and/or fan recirculation. The present control is focused, in particular, on controlling the operation of a fan when no call for heating or cooling is occurring.
BACKGROUNDControls for air handlers such as, programmable thermostats, have increasingly more options and modes available to users, due to the use of fast microprocessors/microcontrollers. Careful programming of microprocessors provides for enhanced heating, cooling and fan control, operations previously unavailable. Thermostats that maximize the frequent circulation of air within a building improve cleanliness and keep the building more comfortable. If there are long off cycles for heating or cooling, air may stagnate and reduce cleanliness because filtration of the air is not occurring during these off cycles. This is because in typical systems, the fan is off between heating and cooling cycles and runs only during the heating or cooling cycle. Some systems include a fan-on mode, in which the fan runs constantly. While running the fan constantly reduces the stagnate air, such an operation may waste energy. Nevertheless, it is known that extending the fan cycle may increase thermal efficiency.
Some systems are known to provide for intermittent fan recirculation modes that are triggered by the end of the last operation of the fan during a heating or cooling cycle. Such a system has the disadvantage of not including a temperature contingent fan control variable and cannot prevent back to back fan on modes. The present invention overcomes the disadvantage of previous systems and provides for a system that increases occupant comfort, while providing efficient fan control.
SUMMARYThe present invention provides for an air conditioning system comprising an air handler, a circulating fan and a control for activating and deactivating heating, cooling and fan recirculate modes. The control is operatively coupled to the air handler and the fan for controlling the air handler and the fan. The control has an interval timer switchable between a timer on (TON) state and a timer off (TOFF) state. Both the TON and. TOFF state durations are variable according to comparisons between room temperature and a set point temperature of the control. The control activates the fan recirculate mode when the following conditions are met:
a) the control is in the fan recirculate mode;
b) heating and cooling of the air conditioning system are not active;
c) the room temperature deviates from the set point temperature of the control.
In an embodiment, the air conditioning system may further comprise an interval spacing mechanism, wherein the room temperature is compared to the set point temperature, in order to avoid back to back fan on states and to allow activation of the fan when the interval timer is in the TON state. In an embodiment, the interval spacing comparison may be calculated according to the following formula, when the control has the heating mode activated:
Ts+0.3≧Tr≧Ts+0.1
where Ts is the set point temperature and Tr is the room temperature.
In an embodiment, the interval spacing comparison may be calculated according to the following formula when the control has the cooling mode activated:
Ts−0.3≦Tr≦Ts−0.1
where Ts is the set point temperature and Tr is the room temperature.
In an embodiment, the interval timer may be activated upon power-up of the control and following expiration of the TON state, the TOFF is activated until expiration and the interval timer operates in a continuous loop with TON and TOFF states sequentially running one after the other and the interval timer being independent of the interval spacing mechanism. In an embodiment, the interval timer TON duration is equal to a first value plus the absolute value of the difference between of the set room point temperature and the room temperature multiplied by a first scaling factor. In an embodiment, the first value is ten (10) minutes and the first scaling factor is 0.1. In an embodiment, the interval timer TOFF duration is equal to a second value plus the absolute value of the difference between the set point temperature and the room temperature multiplied by a second scaling factor. In an embodiment, second the value is twenty (20) minutes and the second scaling factor is 0.2.
In an embodiment, the control may be a thermostat. In an embodiment, the thermostat may include one of a mechanical fan switch for setting the fan to recirculate mode and a touchscreen input for setting the fan to recirculate mode.
The invention further provides for a method for activating recirculate mode comprising the steps of providing a control having an interval timer, the control operatively coupled to an air handler and a fan for activating and deactivating heating, cooling and fan recirculate modes, powering the control in order to the set the interval timer on (TON) state, varying the duration of the TON state by the interval timer to a first value by comparing room temperature with a set point temperature of the control, setting the interval timer to a timer off (TOFF) state, varying the duration of the TOFF state of the interval timer to a second value by comparing the room temperature and set point temperature of the control, setting the control fan recirculate mode, monitoring the control to confirm no heating or cooling of the air conditioning system is active and activating the fan recirculate mode when room temperature deviates from the set point temperature of the control.
In an embodiment, the fan recirculate mode may be activated when the interval timer is in the TON state only after an interval spacing mechanism is executed by comparing the room temperature to the set point temperature of the control. In an embodiment, the interval spacing mechanism value is not preselectable. in an embodiment, the interval spacing mechanism operates according to the following formula when the control has the heating mode activated:
Ts+0.3≧Tr≧Ts+0.1
where Ts is the set point temperature and Tr is the room temperature.
In an embodiment, the TON spacing mechanism operates according to the following formula, when the control has the cooling activated:
Ts−0.3≦Tr≦Ts−0.1
where Ts is the set point temperature and Tr is the room temperature.
In an embodiment, the method may further comprise the step of setting the TON duration that is equal to a first value plus the absolute of the difference of the set point temperature and the room temperature multiplied by a first scaling factor. In an embodiment, the TOFF state is not dependent from an end of the last operation of the fan. In an embodiment, the first and second value and first and second scaling factors are not user selectable.
In an embodiment, the method may further comprise the steps of activating the interval timer upon power-up of the control, activating the TON state until expiration, activating the TOFF state until expiration and operating the interval timer in a continuous loop with TON and TOFF states sequentially running, one after the other and the interval timer being independent of the interval spacing mechanism. In an embodiment, the control may simultaneously process the comparing, monitoring and activating steps. In an embodiment, the control may include a microprocessor for simultaneously processing the comparing, monitoring and activating steps. In an embodiment, the TON duration is between five (5) and fifteen (15) minutes. In an embodiment, the TON duration is approximately fifty-percent (50%) of the TOFF duration. In an embodiment, the TON and TOFF durations are not preselectable by a user. In an embodiment, a fan auto mode and a fan on mode are provided and further comprising the steps of monitoring the control to confirm no auto fan nor fan on mode are active. In an embodiment, the air handler may be a household HVAC system including an air filter and air ducts for circulating indoor and outdoor air.
The invention also provides for a control for activating and deactivating heating, cooling and fan recirculate comprising an interval timer switchable between a timer on (TON) state and timer off (TOFF) state, both the TON and TOFF state durations are variable according to comparisons between room temperature and a set point temperature of the control, and the control activating the fan recirculate mode when the room temperature deviates from the set point temperature of the control.
In an embodiment, the control may provide for an interval spacing mechanism, wherein the room temperature is compared to the set point temperature in order to avoid back to back fan on states and to allow activation of the fan when the interval timer is in the TON state. In an embodiment, the interval tinier is activated upon power-up of the control and following expiration of the TON state, the TOFF state is activated until expiration and the interval timer operates in a continuous loop with TON and TOFF states sequentially running one after the other and the interval timer being independent of the interval spacing mechanism. In an embodiment, the interval timer TON duration may be equal to a first value plus the absolute value of the difference between the set point temperature and the room temperature multiplied by a first scaling factor. In an embodiment, the interval timer TOFF may be equal to a second value plus the absolute value of the difference between the set point temperature and the room temperature multiplied by a second scaling factor.
In a further embodiment the invention provides for a control for activating and deactivating heating, cooling and fan recirculate modes comprising an interval timer switchable between a timer on (TON) state and a timer off (TOFF) state, an interval spacer to prevent back to back fan on states, the interval timer setting TON and TOFF state durations that are variable and are set independently from the operation of the interval spacer and the control activating the fan recirculate mode when the room temperature deviates from the set point temperature of the control following operation of the interval spacer. In an embodiment, the interval spacer may operates according to the following formula:
ABS (Tr−Ts)<Value A
where Ts is the set point temperature and Tr is the room temperature.
In an embodiment, the interval spacer may operate according to the following formula:
CALLON/(CALLON+CALLOFF)<A%.
In an embodiment, the interval spacer may operate according to the following formula:
CALLON/(CALLON+CALLOFF)<B%.
In an embodiment, the interval spacer may operate according to the following formula:
LASTOFF>Value A.
In an embodiment the interval spacer may operate by comparing the room temperature to the set point temperature of the control to allow activation of the fan when the interval timer is in the TON state. In an embodiment, the interval spacer may operate according to the following formula subsequent to a heating mode:
Ts+0.3≧Tr≧Ts+0.1
where Ts is the set point temperature and Tr is the room temperature.
In an embodiment, the interval spacer may operate according to the following formula subsequent to a cooling mode:
Ts−0.3≦Tr≦Ts−0.1
where Ts is the set point temperature and Tr is the room temperature.
The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of embodiments of the invention:
A display area 153 is provided for displaying the day and time. The day and time alpha numeric display 153 may be programmed by the user of the control 100 via the touch buttons. The day and time display area 153 in the embodiment of
The display screen 120 also includes a display area 155 for an alpha numeric display of the set point temperature. As depicted in
The display screen 120 also provides for symbol displays or icons displays 157. For example, the icon 157 provides a graphical depiction of the blades of a fan. In the embodiment depicted in
The display screen 120 also includes an alpha numeric or icon display for the current mode display area 158. As depicted in
The display screen 120 also includes touch sensitive areas that provide for touch buttons each having a generally rectangular outline to identify the button. The display screen includes a system button 161, fan button 162, program button 163, hold button 164, day/time button 165, clean button 166 and configuration button 167. Each of these buttons has an operation that is described by U.S. pending application Ser. No.12/982,959 filed Dec. 31, 2010, which is incorporated herein by reference.
The fan button 162 operates the control with respect to the selection of multiple fan modes. In a preferred embodiment, the fan modes include an auto mode, an on mode and a recirculate mode. By sequentially depressing the fan button 162, a user may scroll through each of these three fan modes and the particular alpha numeric representation or icon for each mode will appear in the fan mode display area 159. As is depicted in the embodiment of
In the fan “on” mode, pole 207 connects fan terminal 208 to 24-volt power from RC terminal 209. In the fan auto and recirculate modes, fan 200 operation is controlled by a latching relay 203 shown with its contacts in the de-energized mode in
The control circuitry is illustrated in
A first embodiment of the control logic of the invention is depicted by the flowchart in
During operation of loop A, if the fan 200 (
As a example of the control described by the above method, if the thermostat 100 first has power applied in the heating mode with the fan 200 (
As a further example of the control described by the above method, if the room temperature drops to 45 degrees, there will be a heating call because the room temperature is less than the set point temperature 330. Fan 200 (
A second embodiment of the control logic of the invention is depicted in
If the fan 200 (
As an example of the control described by the above method, if the thermostat 100 first has power-on applied in the heating mode with the fan 200 (
As a further example of the control described by the above'method, if the room temperature drops to 45 degrees, there will be a heating call at step 540 because the room temperature is less than the set point temperature. Fan 200 (
Ts+0.3≧Tr≧Ts+0.1 (subsequent to a heating mode)
Ts−0.3≦Tr≦Ts−0.1 (subsequent to a cooling mode)
where Ts is the set point temperature, and Tr is the room temperature. Immediately after the call is completed, the room temperature will match the set point temperature, so that the difference between the two will be close to zero, so no call to the interval timer (loop B) is made and there will again be a determination at step 550 as to whether there is a call for cooling, heating, humidification or dehumidification. The fan 200 (
Ts+0.3≧Tr≧Ts+0.1 (subsequent to a heating mode)
Ts−0.3≦Tr≦Ts−0.1 (subsequent to a cooling mode)
where Ts is the set point temperature and Tr is the room temperature. Once the temperature drifts lower, for example, to 49.8, then according to 580, a fan 200 (
A third embodiment of the control logic of the invention is depicted by the flowchart in
During operation of loop A, if the fan 200 (
As an example of the control described by the above method, if the thermostat 100 first has power-on applied in the heating mode with the fan 200 (
As a further example of the control described by the above method, if the room temperature drops to 45 degrees, there will be a heating call because the room temperature is less than the set point temperature. Fan 200 (
A fourth embodiment of the control logic of the invention is depicted by the flowchart in
If the fan 200 (
As an example of the control described by the above method, if the thermostat first has power applied in the heating mode with the fan 200 (
As a further example of the control described by the above method, if the room temperature drops to 45 degrees, there will be a heating call because the room temperature is greater than the set point temperature 930. Fan 200 (
A fifth embodiment of the control logic of the invention is depicted by the flowchart in
If the fan 200 (
As an example of the control described by the above method, if the thermostat first has power-on applied in the heating mode with the fan 200 (
As a further example of the control described by the above method, if the room temperature drops to 45 degrees, there will be a heating call because the room temperature is less than the set point temperature 1130. Fan 200 (
The previous description of the disclosed embodiments is provided to enable a person, skilled in the art to use the present invention. There is modifications to these embodiments would be readily apparent to those skilled in the art, and the generic principle applied herein may be applied to other embodiments within departing from the spirit or the scope of the invention. Thus, the present invention does not intend to be limited to the embodiments shown herein, but is to be accorded to the widest scope consistent with the principles and novel features disclosed herein and as defined by the following claims.
Claims
1. An air conditioning system comprising:
- an air handler;
- a circulating fan;
- a control for activating and deactivating heating, cooling and fan recirculate modes, the control operatively coupled to the air handler and the fan for controlling the air handler and the fan, the control having an interval timer;
- the interval timer switchable between a timer on (TON) state and a timer off (TOFF) state, both the TON and TOFF state durations are variable according to comparisons between room temperature and a set point temperature of the control; the control activating the fan recirculate mode when the following conditions are met:
- a) the control is in fan recirculate mode;
- b) heating and cooling of the air conditioning system are not active; and
- c) the room temperature deviates from the set point temperature of the control.
2. The air conditioning system of claim 1, further comprising an interval spacing mechanism, wherein:
- d) the room temperature is compared to the set point temperature in order to avoid back to back fan on states and to allow activation of the fan when the interval timer is in the TON state.
3. The air conditioning system of claim 2, wherein the interval spacing comparison is made according to the following formula subsequent to a heating mode: where Ts is the set point temperature and Tr is the room temperature.
- Ts+0.3≧Tr≧Ts+0.1
4. The air conditioning system of claim 2, wherein the interval spacing comparison is made according to the following formula subsequent to a cooling mode: where Ts is the set point temperature and Tr is the room temperature.
- Ts−0.3≦Tr≦Ts−0.1
5. The air conditioning system of claim 2, wherein the interval spacing comparison is made according to the following formula: where Ts is the set point temperature and Tr is the room temperature.
- ABS(Tr−Ts)<Value C
6. The air conditioning system of claim 2, wherein the interval spacing comparison is made according to the following formula:
- CALLON/(CALLON+CALLOFF)<A%.
7. The air conditioning system of claim 2, wherein the interval spacing comparison is made according to the following formula:
- CALLON/(CALLON+CALLOFF)<B%.
8. The air conditioning system of claim 2, wherein the interval spacing comparison is made according to the following formula:
- LASTOFF>Value C.
9. The air conditioning system of claim 2, wherein the interval timer is activated upon power-up of the control and following expiration of the TON state, the TOFF state is activated until expiration and the interval timer operates in a continuous loop with TON and TOFF states sequentially running one after the other and the interval timer being independent of the interval spacing mechanism.
10. The air conditioning system of claim 1, wherein the interval timer TON duration is equal to a first value plus the absolute value of the difference between the set point temperature and the room temperature multiplied by a first scaling factor.
11.. The air conditioning system of claim 10, wherein the first value is 10 minutes and the first scaling factor is 0.1.
12. The air conditioning system of claim 10, wherein the interval timer TOFF duration is equal to a second value plus the absolute value of the difference between the set point temperature and the room temperature multiplied by a second scaling factor.
13. The air conditioning system of claim 12, wherein the second value is 20 minutes and the second scaling factor is 0.2.
14. The air conditioning system of the claim 1, wherein the control is a thermostat.
15. The air conditioning system of claim 14, wherein the thermostat includes one of a mechanical fan switch for setting the fan to recirculate mode and a touchscreen input for setting the fan to recirculate mode.
16. A method for activating a fan recirculate mode of an air conditioning system comprising the steps of:
- providing a control having an interval timer, the control operatively coupled to an air handler and a fan for activating and deactivating heating, cooling and fan recirculate modes;
- powering the control in order to set the interval timer to a timer on (TON) state;
- varying the duration of the TON state by the interval timer to a first value by comparing room temperature with a set point temperature of the control;
- setting the interval timer to a timer off (TOFF) state;
- varying the duration of the TOFF state of the interval timer to a second value by comparing the room temperature and the set point temperature of the control;
- setting the control to fan recirculate mode;
- monitoring the control to confirm no heating or cooling of the air conditioning system is active; and
- activating the fan recirculate mode when the room temperature deviates from the set point temperature of the control.
17. The fan activation method of claim 16, wherein the fan recirculate mode is activated when the interval timer is in TON state only after an interval spacing mechanism is executed by comparing the room temperature to the set point temperature of the control.
18. The fan activation method of claim 17, wherein the interval spacing mechanism value is not preselectable.
19. The fan activation method of claim 17, wherein the interval spacing mechanism operates according to the following formula subsequent to a heating mode:
- Ts+0.3≧Tr≧Ts+0.1
- where Ts is the set point temperature and Tr is the room temperature.
20. The fan activation method of claim 17, wherein the interval spacing mechanism operates according to the following formula subsequent to a cooling mode:
- Ts−0.3≦Tr≦Ts−0.1
- where Ts is the set point temperature and Tr is the room temperature.
21. The fan activation method of claim 16, further comprising the step of setting the TON duration that is equal to a first value plus the absolute value of the difference between the set point temperature and the room temperature multiplied by a first scaling factor.
22. The fan activation method of claim 21, wherein the first value is 10 minutes and the first scaling factor is 0.1.
23. The fan activation method of claim 21, further comprising the step of setting the TOFF duration that is equal to a second value plus the absolute value of the difference between the set point temperature and the room temperature multiplied by a second scaling factor.
24. The fan activation method of claim 22, wherein the second value is 20 minutes and the second scaling factor is 0.2.
25. The fan activation method of claim 22, wherein the TOFF state is not dependent from an end of a last operation of the fan.
26. The fan activation method of claim 22, wherein the first and second value and first and second scaling factors are not user selectable.
27. The fan activation method of claim 16, further comprising the steps of:
- activating the interval timer upon power-up of the control;
- activating the TON state until expiration;
- activating the TOFF state until expiration; and
- operating the interval timer in a continuous loop with TON and TOFF states sequentially running one after the other and the interval timer being independent of the interval spacing mechanism.
28. The fan activation method of claim 16, wherein the control simultaneously processes the comparing, monitoring and activating steps.
29. The fan activation method of claim 16, wherein the control includes a microprocessor for simultaneously processing the comparing, monitoring and activating steps.
30. The fan activation method of claim 16, wherein the TON duration is between 5 and 15 minutes.
31. The fan activation method of claim 16, wherein the TON duration is approximately 50% TOFF.
32. The fan activation method of claim 16, wherein the interval timer TON and TOFF durations are not preselectable by a user.
33. The fan activation method of claim 16; wherein a fan auto mode and fan on mode are provided and further comprising the steps of monitoring the control to confirm no auto fan mode or fan on mode are active.
34. The fan activation method of claim 16, wherein the air handler is a HVAC system, including an air filter assembly and air ducts for circulating indoor and outdoor air.
35. The fan activation method of claim 16 further comprising the steps of:
- depressing a fan button of the control;
- selecting the recirculate mode by scrolling through multiple fan modes; and
- upon selection of the fan recirculate mode providing an indication of the mode selected.
36. The fan activation method of claim 35, wherein the control includes a display having an LCD display having touch sensitive areas including a touch button for the fan button.
37. The fan activation method of claim 36, wherein the icon is an alpha numeric presented in a fan mode display area.
38. The fan activation method of claim 36, wherein the icon is a graphical representation of a fan presented on the display.
39. The fan activation method of claim 35, wherein the fan button is a mechanical switch.
40. The fan activation method of claim 16, were in the activation of the fan occurs when a microcontroller of the control energizes a fan terminal in order to power the fan.
41. A control for activating and deactivating heating, cooling and fan recirculate modes comprising:
- an interval timer switchable between a timer on (TON) state and a timer off (TOFF) state, both the TON and TOFF state durations are variable according to comparisons between room temperature and a set point temperature of the control and the control activating the fan recirculate mode when the room temperature deviates from the set point temperature of the control.
42. The control of claim 41, further comprising an interval spacing mechanism, wherein the room temperature is compared to the set point temperature in order to avoid back to back fan on states and to allow activation of the fan when the interval timer is in the TON state.
43. The control of claim 42, wherein the interval timer is activated upon power-up of the control and following expiration of the TON state, the TOFF state is activated until expiration and the interval timer operates in a continuous loop with TON and TOFF states sequentially running one after the other and the interval timer being independent of the interval spacing mechanism.
44. The control of claim 41, wherein the interval timer TON duration is equal to a first value plus the absolute value of the difference between the set point temperature and the room temperature multiplied by a first scaling factor.
45. The control of claim 41, wherein the interval timer TOFF duration is equal to a second value plus the absolute value of the difference between the set point temperature and the room temperature multiplied by a second scaling factor.
46. A control for activating and deactivating heating, cooling and fan recirculate modes comprising:
- an interval timer switchable between a timer on (TON) state and a timer off (TOFF) state;
- an interval spacer to prevent back to back fan on states;
- the interval timer setting TON and TOFF state durations that are variable and are set independently from the operation of the interval spacer; and
- the control activating the fan recirculate mode when the room temperature deviates from the set point temperature of the control following operation of the interval spacer.
47. The control of claim 46, wherein the interval spacer operates according to the following formula:
- ABS(Tr−Ts)<Value A
- where Ts is the set point temperature and Tr is the room temperature.
48. The control of claim 46, wherein the interval spacer operates according to the following formula:
- CALLON/(CALLON+CALLOFF)<A%.
49. The control of claim 46, wherein the interval spacer operates according to the following formula:
- CALLON/(CALLON+CALLOFF)<B%.
50. The control of claim 46, wherein the interval spacer operates according to the following formula:
- LASTOFF>Value A.
51. The control of claim 46, wherein the interval spacer operates by comparing the room temperature to the set point temperature of the control to allow activation of the fan when the interval timer is in the TON state.
52. The control of claim 51, wherein the interval spacer operates according to the following formula subsequent to a heating mode:
- Ts+0.3≧Tr≧Ts+0.1
- where Ts is the set point temperature and Tr is the room temperature.
53. The control of claim 51 wherein the interval spacer operates according to the following formula subsequent to a cooling mode:
- Ts−0.3≦Tr≦Ts−0.1
- where Ts is the set point temperature and Tr is the room temperature.
Type: Application
Filed: Sep 23, 2011
Publication Date: May 17, 2012
Applicant: Braebum Systems, LLC (Montgomery, IL)
Inventor: Ernest E. Soderlund (Hampshire, IL)
Application Number: 13/243,358
International Classification: F24F 11/053 (20060101); F24F 7/007 (20060101);