# US 11,906,189 B2 · System and method for high ventilation of outdoor air > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,906,189 B2 - Document ID: US11906189B2 - Status: Granted - Kind: B2 - Application number: 17/190,904 - Filed: 2021-03-03 - Published: 2022-09-08 - Granted: 2024-02-20 - Earliest claimed: 2021-03-03 - Assignees: Siemens Industry, Inc. - Applicants: Siemens Industry, Inc. - Inventors: Jeffrey Hriljac; Jibo Liu; Richard Pope - Web page: https://patentgrep.com/patent/US11906189B2 ## CPC - F24F 11/0001: {for ventilation (F24F11/30 takes precedence)} - F24F 11/77: by controlling the speed of ventilators - F24F 7/06: with forced air circulation, e.g. by fan {positioning of a ventilator in or against a conduit} - F24F 11/43: of indoor units - F24F 2011/0002: {for admittance of outside air} - F24F 2110/10: Temperature - F24F 2120/00: Control inputs relating to users or occupants - Y02B 30/70: Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating - 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 There is described a system and method for high ventilation using outdoor air in an indoor area comprising an HVAC unit and a controller. The HVAC unit includes at least one damper and a fan. The controller detects an activation of an emergency purge mode, adjusts the at least one air damper to allow a maximum of outside air to flow through the HVAC unit without circulating return air, and establishes a fan speed of the fan for maximum outside airflow through the HVAC unit. The controller also modifies the fan speed of the fan based on an occupant comfort criteria without regard to energy efficiency of the HVAC unit. The fan speed is modified based on a delta enthalpy of the HVAC unit and a nominal capacity of the HVAC unit. ## Claims ### Claim 1 A system for high ventilation using outdoor air in an indoor area comprising: an HVAC unit including at least one damper and a fan; and a controller configured to detect an activation of an emergency purge mode, adjust the at least one air damper to allow a maximum of outside air to flow through the HVAC unit without circulating return air, establish a fan speed of the fan for maximum outside airflow through the HVAC unit, and modify the fan speed of the fan based on an occupant comfort criteria, wherein the fan speed is modified, at least in part, based on a delta enthalpy of the HVAC unit and a nominal capacity of the HVAC unit, and wherein the controller manages the fan speed, using an open loop logic, based on the delta enthalpy of the HVAC unit and the nominal capacity of the HVAC unit; and the controller refines the fan speed, using a closed loop logic, based on at least one of a room temperature of the indoor area or a discharge air temperature of the HVAC unit. ### Claim 2 (depends on 1) The system as described in claim 1, wherein the controller drives the fan at a maximum fan speed. ### Claim 3 (depends on 1) The system as described in claim 1, wherein: the controller provides safety protection for the HVAC unit based on a high mixed/discharge temperature and a low mixed/discharge temperature; and the safety protection including a freeze protection mode for equipment safety. ### Claim 4 (depends on 1) The system as described in claim 1, wherein the controller causes the HVAC unit to purge contaminated viral air from the indoor area. ### Claim 5 (depends on 1) The system as described in claim 1, wherein the delta enthalpy is based on a difference between a discharge air enthalpy of the HVAC unit and an outside air enthalpy of the HVAC unit. ### Claim 6 (depends on 1) The system as described in claim 1, wherein the delta enthalpy does not take humidification of the HVAC unit into consideration. ### Claim 7 A method for high ventilation of outdoor air in an indoor area, the method comprising: detecting an activation of an emergency purge mode; adjusting at least one air damper of an HVAC unit to allow a maximum of outside air to flow through the HVAC unit without circulating return air; establishing a fan speed of a fan of the HVAC unit for maximum outside airflow through the HVAC unit; and modifying the fan speed of the fan based on an occupant comfort criteria, the fan speed being modified, at least in part, based on a delta enthalpy of the HVAC unit and a nominal capacity of the HVAC unit, wherein modifying the fan speed of the fan includes: managing the fan speed, using an open loop logic, based on the delta enthalpy of the HVAC unit and the nominal capacity of the HVAC unit; and refining the fan speed, using a closed loop logic, based on at least one of a room temperature of the indoor area or a discharge air temperature of the HVAC unit. ### Claim 8 (depends on 7) The method as described in claim 7, wherein establishing the fan speed of the fan of the HVAC unit includes driving the fan at a maximum fan speed. ### Claim 9 (depends on 7) The method as described in claim 7, further comprising providing safety protection for the HVAC unit based on a high mixed/discharge temperature and a low mixed/discharge temperature, wherein the safety protection including a freeze protection mode for equipment safety. ### Claim 10 (depends on 7) The method as described in claim 7, wherein modifying the fan speed of the fan includes purging contaminated viral air from the indoor area. ### Claim 11 (depends on 7) The method as described in claim 7, wherein the delta enthalpy is based on a difference between a discharge air enthalpy of the HVAC unit and an outside air enthalpy of the HVAC unit. ### Claim 12 (depends on 7) The method as described in claim 7, wherein the delta enthalpy does not take humidification of the HVAC unit into consideration. ### Claim 13 A non-transitory computer readable medium including executable instructions which, when executed, causes at least one processor to provide high ventilation of outdoor air in an indoor area by: detecting an activation of an emergency purge mode; adjusting at least one air damper of an HVAC unit to allow a maximum of outside air to flow through the HVAC unit without circulating return air; establishing a fan speed of a fan of the HVAC unit for maximum outside airflow through the HVAC unit; and modifying the fan speed of the fan based on an occupant comfort criteria, the fan speed being modified, at least in part, based on a delta enthalpy of the HVAC unit and a nominal capacity of the HVAC unit, wherein modifying the fan speed of the fan includes: managing the fan speed, using an open loop logic, based on the delta enthalpy of the HVAC unit and the nominal capacity of the HVAC unit; and refining the fan speed, using a closed loop logic, based on at least one of a room temperature of the indoor area or a discharge air temperature of the HVAC unit. ### Claim 14 (depends on 13) The medium as described in claim 13, wherein establishing the fan speed of the fan of the HVAC unit includes driving the fan at a maximum fan speed. ### Claim 15 (depends on 13) The medium as described in claim 13, further comprising providing safety protection for the HVAC unit based on a high mixed/discharge temperature and a low mixed/discharge temperature, wherein the safety protection including a freeze protection mode for equipment safety. ### Claim 16 (depends on 13) The medium as described in claim 13, wherein modifying the fan speed of the fan includes purging contaminated viral air from the indoor area. ### Claim 17 (depends on 13) The medium as described in claim 13, wherein the delta enthalpy is based on a difference between a discharge air enthalpy of the HVAC unit and an outside air enthalpy of the HVAC unit.