Systems and methods for managing conditions in enclosed space

Patent metadata

Field	Value
Publication number	US-11015845-B2
Application number	US-201816230958-A
Country	US
Kind code	B2
Filing date	Dec 21, 2018
Priority date	Jun 20, 2014
Publication date	May 25, 2021
Grant date	May 25, 2021

Abstract

Systems and methods for controlling temperature in an enclosed space can include an air-to-air heat exchanger (AAHX) and a direct evaporative cooler (DEC). The DEC can be located in a scavenger or outdoor air stream such that the DEC cools the outdoor air, which is then used to cool or reject heat from a process air stream passing through the AAHX. In an example, the AAHX can be a sensible wheel. In another example, the AAHX can be a counter-flow flat plate. The system can operate in various modes, including an economizer mode and an evaporation mode, depending, in part, on the outdoor air conditions and a load on the system. In some examples, the system can include a DX coil to provide additional cooling to the process air in another operating mode.

First claim

What is claimed is:

1. A system for controlling temperature in an enclosed space, the system comprising:
a process air flow path having a process air inlet and outlet;
a set point temperature for the process air at the process air outlet;
a scavenger air flow path having a scavenger air inlet and outlet, the scavenger air flow path and process air flow path separate from one another in the system;
an air-to-air heat exchanger (AAHX) arranged in the process air flow path and in the scavenger air flow path, the scavenger air conditioning the process air using the AAHX, the AAHX comprising at least one of a counter-flow flat-plate heat exchanger and a sensible wheel;
a direct evaporative cooler (DEC) arranged in the scavenger air flow path between the AAHX and the scavenger air inlet, the DEC selectively conditioning the scavenger air prior to the scavenger air passing through the AAHX; and
a direct expansion cooling device arranged in the process air flow path downstream of the AAHX, the direction expansion cooling device selectively providing further conditioning of the process air exiting the AAHX,
wherein an operating mode of the system is selected from a plurality of operating modes based on a comparison of a measured temperature at the process air outlet and the set point temperature.

2. The system of claim 1 wherein the plurality of operating modes includes a first mode of operation in which only the AAHX is needed to sufficiently condition the process air such that the measured temperature at the process air outlet is at or near the set point temperature.

3. The system of claim 2 wherein the first mode of operation includes the scavenger air bypassing the DEC and the process air bypassing the direct expansion cooling device.

4. The system of claim 1 wherein the plurality of operating modes includes a second mode of operation in which operation of the AAHX and the DEC, without operation of the direct expansion cooling device, is sufficient such that the measured temperature at the process air outlet is at or near the set point temperature.

5. The system of claim 4 wherein the second mode of operation includes bypassing the direct expansion cooling device.

6. The system of claim 1 wherein the plurality of operating modes includes a third mode of operation in which the direct expansion cooling device is operating to provide further conditioning of the process air exiting the AAHX.

7. The system of claim 1 wherein the direct expansion cooling device comprises:
a DX coil arranged in the process air flow path between the AAHX and the process air outlet; and
a condenser coil arranged in the scavenger air flow path between the AAHX and the scavenger air outlet.

8. The system of claim 1 wherein the set point temperature is about 75 degrees Fahrenheit.

9. The system of claim 1 wherein the set point temperature includes a temperature range for the process air at the process air outlet.

10. The system of claim 9 wherein the acceptable temperature range is between 75 and 78 degrees Fahrenheit.

11. A control system for controlling a temperature of supply air delivered to an enclosed space, the control system comprising:
a sensible wheel arranged in a flow path of process air between a process air inlet and outlet and in a flow path of scavenger air between a scavenger air inlet and outlet, the scavenger air conditioning the process air using the sensible wheel, the scavenger air flow path and process air flow path separated from one another in the system;
a plurality of operating modes for operating the system, an operating mode selected from the plurality of operating modes based on a comparison of a measured temperature of the process air at the process air outlet to a set point temperature;
a direct evaporative cooler (DEC) arranged in the scavenger air flow path upstream of the sensible wheel, the direct evaporative cooler selectively conditioning the scavenger air prior to the scavenger air passing through the sensible wheel depending on the selected operating mode; and
a DX coil arranged in the process air flow path downstream of the sensible wheel, the DX coil selectively conditioning the process air exiting the sensible wheel depending on the selected operating mode.

12. The control system of claim 11 further comprising a first bypass feature for the scavenger air to bypass the DEC in a first operating mode.

13. The control system of claim 12 further comprising a second bypass feature for the process air to bypass the DX coil in a first operating mode and a second operating mode.

14. The control system of claim 11 further comprising a condenser coil arranged in the scavenger air flow path between the sensible wheel and the scavenger air outlet, the condenser coil configured to cool a refrigerant from the DX coil, using the scavenger air.

15. A method for controlling a temperature of supply air delivered to an enclosed space, the method comprising:
passing scavenger air and process air through an air-to-air heat exchanger (AAHX) arranged in a conditioning system, the scavenger air passing through a first portion of the conditioning system, the process air passing through a second portion of the conditioning system separate from the first portion, the AAHX arranged partially in the first portion and partially in the second portion, and the scavenger air cools the process air in the AAHX;
selectively passing the scavenger air through a direct evaporative cooler (DEC) arranged in the first portion, depending on an operating mode of the conditioning system;
selectively passing the process air through a DX coil arranged in the second portion, depending on the operating mode of the conditioning system;
measuring a temperature of the process air at a process air outlet of the second portion;
comparing the measured process air temperature to a set point temperature of the process air at the process air outlet; and
determining the operating mode of the conditioning system from among first, second and third operating modes, the operating mode determined as a function of a difference between the measured process air temperature and the set point temperature.

16. The method of claim 15 wherein the first operating mode excludes operation of the DEC and DX coil, the second operating mode excludes operation of the DX coil, and the third operating mode includes operation of the AAHX, DEC and DX coil.

17. The method of claim 16 further comprising:
directing the process air through the second portion such that the process air bypasses the DX coil in the first and second operating modes.

18. The method of claim 16 further comprising:
directing the scavenger air through the first portion such that the scavenger air bypasses the DEC in the first operating mode.

19. The method of claim 15 wherein determining the operating mode of the conditioning system includes determining a minimal number of the AAHX, DEC and DX coil needed to adequately condition the process air such that the measured temperature at the process air outlet is at or near the set point, temperature.

Assignees

• Nortek Air Solutions Canada Inc
• Nortek Air Solations Canada Inc

Inventors

• Ghadiri Moghaddam Davood
• Lepoudre Philip Paul
• Gerber Manfred

Classifications

• F24F1/0059

  characterised by heat exchangers · CPC title

• F25B25/005 Primary

  using primary and secondary systems · CPC title

• Y02B30/56

  Heat recovery units · CPC title

• H05K7/20745

  within rooms for removing heat from cabinets, e.g. by air conditioning device · CPC title

• F24F12/006

  using an air-to-air heat exchanger (F24F12/002 takes precedence) · CPC title