# US 9,435,557 B2 · Control unit for an HVAC system comprising an economizer and method for operating such control unit

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- Number: US 9,435,557 B2
- Document ID: US9435557B2
- Status: Granted
- Kind: B2
- Application number: 13/749,007
- Filed: 2013-01-24
- Published: 2014-07-24
- Granted: 2016-09-06
- Earliest claimed: 2013-01-24
- Assignees: Belimo Holding AG
- Applicants: BELIMO Holding AG
- Inventors: Daniel Albrecht; Ronald Aeberhard; Guido Hofstetter; Darryl Deangelis
- Web page: https://patentgrep.com/patent/US9435557B2

## CPC

- F24F 11/0001: {for ventilation (F24F11/30 takes precedence)}
- F24F 11/52: Indication arrangements, e.g. displays
- F24F 11/88: Electrical aspects, e.g. circuits
- F24F 7/08: with separate ducts for supplied and exhausted air {with provisions for reversal of the input and output systems}
- F24F 11/30: for purposes related to the operation of the system, e.g. for safety or monitoring
- F24F 2011/0006: {using low temperature external supply air to assist cooling}
- F24F 2110/20: Humidity
- F24F 2110/22: of the outside air
- F24F: AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING (removing dirt or fumes from areas where they are produced B08B15/00; vertical ducts for carrying away waste gases from buildings E04F17/02; tops for chimneys or ventilating shafts, terminals for flues F23L17/02)

## Abstract

A control unit (22) for an HVAC system (10) comprises an economizer (EC), which economizer (EC) is configured to introduce outdoor air (OA) into the HVAC system (10) for cooling and/or ventilation purposes in a manner controlled by said control unit (22), said control unit (22) comprising a base module (23) with: a control circuit (24), a man machine interface (25) connected to said control circuit (24), and first I/O means for connecting at least one sensor (32, . . . , 36) of said HVAC system to said control circuit (24) and for delivering at least one control signal from said control circuit (24) to control the operation of said economizer (EC). Said base module (23) is configured to optionally receive at least one extension module (26, 27, 28), which can be snapped on and electrically connected to said base module (23) for expanding the functionality of said control unit (22).

## Claims

### Claim 1

A control unit (22) for a heating, ventilation and air conditioning (HVAC) system (10) comprising an economizer (EC), which economizer (EC) is configured to introduce outdoor air (OA) into the HVAC system (10) for cooling and/or ventilation purposes in a manner controlled by said control unit (22), said control unit (22) comprising a base module (23) with: a control circuit (24), a man machine interface (25) connected to said control circuit (24), and first input/output (I/O) means (39, CR1, CR2, CR3) for connecting at least one sensor (32, . . . ,36) of said HVAC system to said control circuit (24) and for delivering at least one control signal from said control circuit (24) to control the operation of said economizer (EC), whereby said base module (23) is configured to optionally receive at least one extension module (26, 27, 28), which can be snapped on and electrically connected to said base module (23) for expanding the functionality of said control unit (22) and wherein said first I/O means (39, CR1, CR2, CR3) comprises connecting means (1Act, 2Act, 3Act, 5Act) for connecting an actuator (17), connecting means (Y1, Y2, W1) for connecting a thermostat (31), and at least one temperature connecting means or humidity connecting means.

### Claim 2 (depends on 1)

Control unit as claimed in claim 1, wherein said base module (23) is configured to receive said at least one extension module (26, 27, 28) such that the electrical connection between said at least one extension module (26, 27, 28) and said base module (23) is automatically established, when said at least one extension module (26, 27, 28) is snapped on said base module (23).

### Claim 3 (depends on 2)

Control unit as claimed in claim 2, wherein a plug-in connector (56, 57, 58, 63) is provided for electrically connecting said base module (23) and said at least one extension module (26, 27, 28), one part of said plug-in connector (56, 57, 58, 63) being integrated into said base module (23) and the other part of said plug-in connector (56, 57, 58, 63) being integrated into said at least one extension module (26, 27, 28).

### Claim 4 (depends on 1)

Control unit as claimed in claim 1, wherein said base module (23) is configured to receive a plurality of extension modules (26, 27, 28), wherein plug-in connectors (56, 57, 58, 63) are provided for electrically connecting said base module (23) and each of said extension modules (26, 27, 28), one part of each plug-in connector (56, 57, 58, 63) being integrated into said base module (23) and the other part of each plug-in connector (56, 57, 58, 63) being integrated into an extension module (26, 27, 28), whereby said plug-in connectors (56, 57, 58, 63) are individualized so that each plug-in connector (56, 57, 58, 63) can only be used with one type of extension module.

### Claim 5 (depends on 3)

Control unit as claimed in claim 3, wherein said base module (23) is provided with first latching means (62) and said at least one extension module (26, 27, 28) is provided with second latching means (61) configured to co-operate with said first latching means (62) such that said at least one extension module (26, 27, 28) is locked in place on said base module (23), when it is plugged into said plug-in connector (56, 57, 58, 63).

### Claim 6 (depends on 5)

Control unit as claimed in claim 5, wherein said first and second latching means (61, 62) comprise an elastically bendable snapping clip (61) and one or more catches (62), whereby said snapping clip (61) glides over and latches behind said catches (62), when said at least one extension module (26, 27, 28) is plugged into said plug-in connector (56, 57, 58, 63), and whereby said at least one extension module (26, 27, 28) can be released by elastically bending said snapping clip (61).

### Claim 7 (depends on 6)

Control unit as claimed in claim 6, wherein said elastic snapping clip (61) is provided at said at least one extension module (26, 27, 28), and said catches (62) are arranged at said base module (23).

### Claim 8 (depends on 1)

Control unit as claimed in claim 1, wherein said at least one extension module (26, 27, 28) is provided with second I/O means (CR4, CR5; 50, 51, 52) for electrically connecting said at least one extension module (26, 27, 28) and thereby said base module (23) with further units (18, 21, 29, 30, 37) being relevant for the operation of the HVAC system (10).

### Claim 9 (depends on 8)

Control unit as claimed in claim 8, wherein said at least one extension module (26) is configured to enable a demand controlled ventilation (DCV) operation of the HVAC system (10), and said second I/O means comprises input means for a CO2 sensor (37) and output means for controlling an exhaust fan (21) within said HVAC system (10).

### Claim 10 (depends on 9)

Control unit as claimed in claim 9, wherein said second I/O means comprise further output means for controlling an indoor fan (18) within said HVAC system (10).

### Claim 11 (depends on 8)

Control unit as claimed in claim 8, wherein said at least one extension module (27) is configured to enable a communication with remote devices (29, 30).

### Claim 12 (depends on 11)

Control unit as claimed in claim 11, wherein said remote devices (29, 30) comprise an alarm device (30).

### Claim 13 (depends on 11)

Control unit as claimed in claim 11, wherein said remote devices (29, 30) comprise a remote unit (29) for exchanging data with said control unit (22).

### Claim 14 (depends on 1)

Control unit as claimed in claim 1, wherein said base module (23) comprises a base plate (53) and a housing (54) mounted on said base plate (53), which housing (54) encloses said control circuit (24) and said man machine interface (25), whereby said housing (54) comprises on its upper side an I/O platform (38), on which said first I/O means (39, CR1, CR2, CR3) is arranged, and which is configured to receive said at least one extension module (26, 27, 28), and further comprises a man-machine interface (MMI) housing part (40), which projects from said I/O platform (38) and contains said man machine interface (25).

### Claim 15 (depends on 14)

Control unit as claimed in claim 14, wherein said first I/O means comprises a plurality of connector rows (CR1, CR2, CR3), which are arranged in a separate I/O area (39).

### Claim 16 (depends on 15)

Control unit as claimed in claim 15, wherein said at least one extension module (26, 27, 28) can be snapped on said base module (23) outside said I/O area (39) without changing the footprint of said base module (23).

### Claim 17 (depends on 15)

Control unit as claimed in claim 15, wherein each said connector row (CR1, CR2, CR3) comprises a plurality of individual male spade connectors.

### Claim 18 (depends on 1)

Control unit as claimed in claim 1, wherein said control circuit (24) and said sensor connecting means (+SAT, −SAT; +OAT, −OAT; +OAH, −OAH; +RAT, −RAT; +RAH, −RAH) are configured to be connected to analog sensors.

### Claim 19 (depends on 1)

Control unit as claimed in claim 1, wherein said connecting means (1Act, 2Act, 3Act, 5Act) for connecting an actuator (17) comprises a separate connector (5Act) for receiving a feedback signal from said actuator (17), said feedback signal containing information about the actual position of said actuator (17).

### Claim 20 (depends on 1)

Control unit as claimed in claim 1, wherein said first I/O means (39, C1, C2, C3) further comprises eighth connecting means (CC1, CC2) for connecting first and second compressors of a two-stage cooling device (19) within said HVAC system (10).

### Claim 21 (depends on 1)

Control unit as claimed in claim 1, wherein said man machine interface (25) comprises a display (46) for displaying menu points, onboard information, set values and real time operating information, a plurality of push buttons (41, 42, 47, 48, 49) for inputting various commands, and a plurality of optical indicators (43, 44, 45) for indicating status information.

### Claim 22 (depends on 21)

Control unit as claimed in claim 21, wherein said display (46) is an enhanced transflective backlit liquid crystal display (LCD display), with two rows of 16 characters each.

### Claim 23 (depends on 21)

Control unit as claimed in claim 21, wherein said plurality of push buttons (41, 42, 47, 48, 49) comprises a separate help button (47) for retrieving and displaying context sensitive help information stored with said control circuit (24).