Apparatus and method for controlling temperature and humidity of a conditioned space

• US 6,295,823 B1
• Filed: 03/08/2000
• Issued: 10/02/2001
• Est. Priority Date: 03/16/1999
• Status: Expired due to Fees

• Current Assignee: CH2M Hill Incorporated (CH2M Hill Companies Limited)
• Original Assignee: CH2M Hill Incorporated (CH2M Hill Companies Limited)
• Inventors: Harris, Michael R., Odom, Julius David, MacPhaul, David
• Primary Examiner(s): WAYNER, WILLIAM E
• Application Number:
  US09/520,594
• Time in Patent Office: 573 Days
• Field of Search: 236/44.C, 236/44.A, 236/1.R, 621/766, 621/80, 165/249, 165/225, 165/135, 454/256, 454/236
• US Class Current: 62/176.6
• CPC Class Codes: F24F 1/0033 having two or more fans
• CPC Class Codes: F24F 1/0035 characterised by introduction of outside air to the room
• CPC Class Codes: F24F 1/0038 in combination with simultaneous exhaustion of inside air
• CPC Class Codes: F24F 1/005 mounted on the floor; standing on the floor
• CPC Class Codes: F24F 1/0057 mounted in or on a wall
• CPC Class Codes: F24F 1/0063 by the mounting or arrangement of the heat exchangers
• CPC Class Codes: F24F 1/0073 characterised by the mounting or arrangement of filters
• CPC Class Codes: F24F 1/0083 with dehumidification means
• CPC Class Codes: F24F 2011/0002 for admittance of outside air
• CPC Class Codes: F24F 3/153 with subsequent heating, i.e. with the air, given the required humidity in the central station, passing a heating element to achieve the required temperature
• CPC Class Codes: G05D 27/02 characterised by the use of electric means

Abstract

An apparatus for controlling temperature and humidity of a conditioned space uses an outside air cooling coil circuit in fluid communication with coolant from a cooling supply. Outside air is introduced over the outside air cooling coil circuit through a damper having open and closed positions. A valve in fluid communication with the coolant supply and the outside air cooling coil circuit has an open setting for permitting and a closed setting for preventing the circulation of coolant through the outside air cooling coil circuit. An HVAC unit control is operatively associated with the valve and the damper for controlling their operation. An occupancy control generates a signal indicating the presence of a human within the conditioned space and is operatively associated with the HVAC unit control. The HVAC unit control, in response to a signal from the occupancy control indicating the presence of a human within the conditioned space, causes the damper to be open and enables the valve to be switched between the closed and open settings. A method of conditioning the air within a conditioned space provides an outside air cooling coil circuit. The presence or absence of a human within the conditioned space is continuously monitored. When a human is present, outside air is continuously directed onto the outside air cooling coil circuit and into the conditioned space. The need to decrease the humidity of the outside air directed onto the air cooling coil circuit is continuously monitored so as to enable the humidity within the conditioned space to be maintained below a select humidity threshold. Coolant is circulated through the outside air cooling coil circuit when a human is present within the conditioned space and the humidity within the conditioned space is determined to be above the select humidity threshold.

Claims

1. A heating, ventilation and air conditioning (HVAC) unit for a conditioned space comprising:

a cooling coil divided into a first cooling coil circuit and a second cooling coil circuit each in fluid communication with coolant from a coolant supply, each of the first and second cooling coil circuits having a leading and trailing surface, the leading surfaces being defined by first and second perpendicular axes with the coil being divided along the first axis into the first and second circuits;

an outside air intake introducing air from outside to inside the conditioned space, the outside air intake being positioned to distribute outside air to substantially the center of the leading surface of the first cooling coil circuit along the second axis;

a return air intake for introducing return air from inside the conditioned space to the leading surface of the second circuit of the coil;

a first valve in fluid communication with the coolant supply and the first cooling coil circuit, the first valve having an open setting permitting and a closed setting preventing the circulation of coolant through the first cooling coil circuit;

humidity control means coupled to the first valve for actuating the first valve between the open and closed settings as a function of a need to decrease the humidity of the outside air introduced into the conditioned space; and

an exhaust introducing dehumidified outside and return air to the conditioned space.

2. The HVAC unit of claim 1 further comprising:

a second valve in fluid communication with the coolant supply of the second cooling coil circuit, the second valve selectively permitting and preventing the circulation of coolant through the second cooling coil circuit; and

temperature control means coupled to the second valve for actuating the second valve between the open and closed settings as a function of a need to decrease the temperature of the conditioned space.

3. The HVAC unit of claim 1 further comprising a fan in fluid communication with the exhaust for drawing outside air into the outside air intake and return air into the return air intake.

4. The HVAC unit of claim 1 further comprising a heater in fluid communication with the exhaust for heating the outside and return air before introduction to the conditioned space.

5. The HVAC system of claim 3 further comprising a damper in fluid communication with the outside air intake having an open position enabling outside air to flow through the outside air intake and a closed position preventing outside air from flowing through the outside air intake, and an activation switch located remote from the unit coupled with the damper, the activation switch having a first setting causing the damper to be open and second setting causing the damper to be closed.

6. The HVAC system of claim 3 further comprising a damper in fluid communication with the outside air intake having an open position enabling outside air to flow through the outside air intake and a closed position preventing outside air from flowing through the outside air intake, and an occupancy sensor within the conditioned space for sensing the presence or absence of a human within the conditioned space coupled to the damper, the occupancy sensor when sensing the presence of a human within the conditioned space causing the damper to be open and when sensing the absence of a human within the conditioned space causing the damper to be closed.

7. A method of conditioning the air within a conditioned space comprising:

a) providing an outside air cooling coil circuit and a return air cooling coil circuit;

b) monitoring the conditioned space for the presence or absence of a human;

c) when a human is present, continuously directing outside air onto the outside air cooling coil circuit and into the conditioned space;

d) continuously monitoring the need to decrease the humidity of the outside air directed onto the outside air cooling coil circuit to maintain the humidity within the conditioned space below a select humidity threshold; and

e) circulating coolant through the outside air cooling coil circuit when

     1) a human present in the conditioned space and

     2) the humidity within the conditioned space is determined to be above the select humidity threshold.

8. The method of claim 7 further comprising when a human is present, continuously spilling air from the conditioned space to outside the conditioned space.

9. The method of claim 7 firther comprising when a human is present, continuously directing air from inside the conditioned space over the return air cooling coil circuit and back into the conditioned space.

10. The method of claim 9 further comprising:

mixing the outside air from over the outside air cooling coil circuit and return air from over the return air cooling coil circuit; and

introducing the mixed air into the conditioned space.

11. The method of claim 9 further comprising:

continuously monitoring the temperature inside the conditioned space; and

circulating coolant through the return air cooling coil circuit only when the temperature inside the conditioned space exceeds a select temperature.

12. The method of claim 7 wherein step b) is performed by providing an occupancy sensor in the conditioned space.

13. The method of claim 12 wherein steps c) and e) are performed by electrically coupling the occupancy sensor to a damper in fluid communication with the outside air and a means for circulating coolant through the outside air cooling coil circuit.

14. A heating, ventilation and air conditioning (HVAC) unit for a conditioned space comprising:

an outside air cooling coil circuit in fluid communication with coolant from a coolant supply, the outside air cooling coil circuit having a leading and a trailing surface;

an outside air intake introducing air from outside to inside the conditioned space, the outside air intake being positioned to distribute outside air to the leading surface of the outside air cooling coil circuit;

a damper in fluid communication with the outside air intake having an open position permitting and a closed position preventing outside air to enter the outside air intake;

a valve in fluid communication with the coolant supply and outside air cooling coil circuit, the valve having an open setting permitting and a closed setting preventing the circulation of coolant through the outside air cooling coil circuit;

an exhaust introducing the outside air from the trailing surface of the outside air cooling coil circuit to the conditioned space;

an HVAC unit control operatively associated with the valve and the damper for controlling their operation; and

an occupancy control means for generating a signal indicating the presence of a human within the conditioned space operatively associated with the HVAC until control, the HVAC unit control, in response to a signal from the occupancy control indicating the presence of a human within the conditioned space, causing the damper to be in the open position and enabling the valve to be switched between the closed and open settings.

15. The HVAC unit of claim 14 further comprising humidity control means coupled to the HVAC unit control for generating a signal indicating the need to decrease humidity within the conditioned space, the HVAC control in response to the signal actuating the valve to the open setting.

16. The HVAC unit of claim 14 wherein when the occupancy control does not generate a signal indicating the presence of a human within the conditioned space, the HVAC unit control actuates the damper to its closed position and actuates the valve to the closed setting.