# US 11,441,809 B2 · Auxiliary economizer for an HVAC system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,441,809 B2 - Document ID: US11441809B2 - Status: Granted - Kind: B2 - Application number: 16/279,790 - Filed: 2019-02-19 - Published: 2020-08-20 - Granted: 2022-09-13 - Earliest claimed: 2019-02-15 - Assignees: Johnson Controls Tyco IP Holdings LLP - Applicants: Johnson Controls Technology Company - Inventors: Rammohan Sethuraj; Pankaj D. Nalamwar; Shashank B. Kadam; Sriram Ramanujam - Web page: https://patentgrep.com/patent/US11441809B2 ## CPC - F24F 12/001: {with heat-exchange between supplied and exhausted air} - F24F 3/00: Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems (room units F24F1/00) - F24F 7/06: with forced air circulation, e.g. by fan {positioning of a ventilator in or against a conduit} - F24F 11/70: Control systems characterised by their outputs; Constructional details thereof - F24F 13/04: Air-mixing units (F24F13/06 takes precedence) - F24F 13/14: built up of tilting members, e.g. louvre - F24F 2012/007: {using a by-pass for bypassing the heat-exchanger} - F24F 2110/12: of the outside air - F24F 2140/50: Load - Y02B 30/54: Free-cooling systems - 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) - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS ## Abstract A heating, ventilation, and/or air conditioning (HVAC) unit may include a supply fan section having a supply fan disposed therein to force a supply air flow through a discharge plenum of the HVAC unit. The HVAC unit may also include an economizer positioned adjacent the supply fan section to receive an outdoor air flow and direct the outdoor air flow into the supply fan section. ## Claims ### Claim 1 A heating, ventilation, and/or air conditioning (HVAC) unit, comprising: a supply fan configured to force a supply air flow through a discharge plenum of the HVAC unit; an economizer positioned proximate the supply fan, wherein the economizer is configured to receive an outdoor air flow and direct the outdoor air flow toward the supply fan, such that the outdoor air flow bypasses an evaporator coil of the HVAC unit; and a mixing chamber having a return air inlet and an outdoor air intake, wherein the mixing chamber is fluidly coupled to the supply fan, wherein the mixing chamber is configured to mix a first air flow from the return air inlet and a second air flow from the outdoor air intake, and wherein the evaporator coil is disposed downstream of the mixing chamber and upstream of the supply fan. ### Claim 2 (depends on 1) The HVAC unit of claim 1, wherein the economizer is configured to facilitate the outdoor air flow directly to the supply fan. ### Claim 3 (depends on 1) The HVAC unit of claim 1, wherein the mixing chamber forms a first air flow path toward the supply fan, and the economizer forms a second air flow path toward the supply fan, separate from the first air flow path. ### Claim 4 (depends on 1) The HVAC unit of claim 1, wherein the economizer is a first economizer, and the outdoor air intake is a second economizer. ### Claim 5 (depends on 1) The HVAC unit of claim 1, wherein the economizer is affixed to a top surface of the HVAC unit. ### Claim 6 (depends on 1) The HVAC unit of claim 1, wherein the economizer is affixed to a side surface of the HVAC unit. ### Claim 7 (depends on 1) The HVAC unit of claim 1, comprising a controller configured to regulate operation of the economizer based on an operating mode of the HVAC unit, a conditioning capacity utilization of the HVAC unit, a temperature of the outdoor air flow, or a combination thereof. ### Claim 8 (depends on 1) The HVAC unit of claim 1, wherein the economizer includes a damper, and wherein the damper is configured to be adjusted to regulate an amount of the outdoor air flow directed toward the supply fan. ### Claim 9 (depends on 8) The HVAC unit of claim 8, wherein the damper is fully open during a free-cooling mode of the HVAC unit. ### Claim 10 (depends on 7) The HVAC unit of claim 7, wherein the controller is configured to determine the conditioning capacity utilization based on a compressor load. ### Claim 11 (depends on 7) The HVAC unit of claim 7, wherein the controller is configured to compare the conditioning capacity utilization to a threshold system load to determine whether the economizer should be utilized. ### Claim 12 An economizer, comprising: an air inlet configured to receive an environmental air flow; an air outlet configured to direct the environmental air flow into a heating, ventilation, and/or air conditioning (HVAC) unit proximate a blower section of the HVAC unit, such that the environmental air flow bypasses an evaporator coil of the HVAC unit prior to being discharged via a plenum section of the HVAC unit; a damper configured to regulate a flow rate of the environmental air flow from the air inlet to the air outlet; and a controller configured to regulate a position of the damper, wherein the controller is configured to open the damper when the HVAC unit is operated at a first conditioning capacity utilization less than a threshold value, and the controller is configured to open a second damper of a second economizer of the HVAC unit when the HVAC unit is operated at a second conditioning capacity utilization greater than the threshold value. ### Claim 13 (depends on 12) The economizer of claim 12, wherein the controller is configured to determine the threshold value based on a temperature of the environmental air flow. ### Claim 14 (depends on 12) The economizer of claim 12, wherein the controller is configured to close the damper of the economizer based on the second conditioning capacity utilization being greater than the threshold value. ### Claim 15 (depends on 12) The economizer of claim 12, wherein the HVAC unit is an existing HVAC unit, and the economizer is configured to be retrofitted to the existing HVAC unit. ### Claim 16 (depends on 12) The economizer of claim 12, comprising a filter proximate the air outlet. ### Claim 17 (depends on 12) The economizer of claim 12, wherein the controller is configured to determine the first conditioning capacity utilization based on a compressor load of the HVAC unit or a blower motor load of a blower of the blower section. ### Claim 18 (depends on 12) The economizer of claim 12, wherein the second damper is configured to direct a second environmental air flow to the evaporator coil of the HVAC unit. ### Claim 19 A heating, ventilation, and/or air conditioning (HVAC) unit, comprising: a first economizer configured to direct a first environmental air flow into an air flow path of the HVAC unit; a second economizer configured to direct a second environmental air flow into the air flow path; and a conditioning section including an evaporator coil, wherein the conditioning section is disposed between the first economizer and the second economizer, relative to a direction of air flow through the air flow path, wherein the evaporator coil is configured to condition the air flow. ### Claim 20 (depends on 19) The HVAC unit of claim 19, wherein the second economizer is positioned adjacent to a blower section of the HVAC unit. ### Claim 21 (depends on 19) The HVAC unit of claim 19, wherein the first economizer is configured to direct the first environmental air flow to an energy recovery wheel, a hot gas reheat coil, or both prior to the conditioning section. ### Claim 22 (depends on 19) The HVAC unit of claim 19, wherein the first economizer includes a first damper, and the second economizer includes a second damper. ### Claim 23 (depends on 22) The HVAC unit of claim 22, comprising a controller configured to regulate respective positions of the first damper and the second damper, wherein the controller is configured to open the first damper and close the second damper based on opening of the first damper, and the controller is configured to open the second damper and close the first damper based on opening of the second damper. ### Claim 24 (depends on 22) The HVAC unit of claim 22, comprising a controller configured to regulate respective positions of the first damper and the second damper, wherein the controller is configured to open the first damper when the HVAC unit is operated at a first conditioning capacity utilization greater than a threshold value, and the controller is configured to open the second damper when the HVAC unit is operated at a second conditioning capacity utilization less than the threshold value. ### Claim 25 (depends on 24) The HVAC unit of claim 24, wherein the threshold value is determined, via the controller, based on an environmental air temperature.