# US 8,464,783 B2 · Method and arrangement for optimizing heat transfer properties in heat exchange ventilation systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,464,783 B2 - Document ID: US8464783B2 - Status: Granted - Kind: B2 - Application number: 12/282,384 - Filed: 2007-03-09 - Published: 2009-02-19 - Granted: 2013-06-18 - Earliest claimed: 2006-03-10 - Applicants: Mikael Nutsos - Inventors: Mikael Nutsos - Web page: https://patentgrep.com/patent/US8464783B2 ## CPC - F24F 12/002: {using an intermediate heat-transfer fluid} - C09K 5/20: Antifreeze additives therefor, e.g. for radiator liquids (for application to surfaces C09K3/18; inhibiting corrosion by liquids C23F11/00) - F28F 23/00: Features relating to the use of intermediate heat-exchange materials, e.g. selection of compositions (heat-transfer, heat-exchange or heat-storage materials C09K5/00) - F28F 27/00: Control arrangements or safety devices specially adapted for heat-exchange or heat-transfer apparatus (control arrangements in general G05) - F24F 11/41: Defrosting; Preventing freezing - Y02B 30/56: Heat recovery units - Y02P 20/10: Process efficiency - Y10T 137/0329: Mixing of plural fluids of diverse characteristics or conditions - Y10T 137/2562: Dividing and recombining - 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) - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE - F28F: DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION (water and air traps, air venting F16) - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract The present invention relates to a method and arrangement of optimizing the level of anti freeze agent in a heat transfer fluid in a heat exchange system The method comprises determining (305) a wanted level of anti freeze agent at least partly based on the temperature of the media to which the heat exchange system will deliver heat, controlling (310) the current level of the anti freezing agent in the heat transfer fluid. Anti freezing agent is added 315:1 to the heat transfer fluid if the current level is a predetermined amount lower than the wanted level, and removed 315:2 from the heat transfer fluid if the current level is a predetermined amount higher than the wanted level. ## Claims ### Claim 1 A method of optimizing a level of an antifreeze agent in a heat transfer fluid of a heat exchange system of a ventilation system, comprising the steps of: operating the heat exchange system of the ventilation system i) to deliver heat to incoming air by outgoing air heating the heat transfer fluid, and ii) for the heat transfer fluid to transfer the heat collected from the outgoing air to warm incoming air, the operating step including monitoring a temperature of the incoming air, wherein the level of the antifreeze agent in the heat transfer fluid is dependent on the temperature of the incoming air; monitoring a temperature of the heat transfer fluid; determining a wanted level of the antifreeze agent based on the monitored temperature of the incoming air; and controlling a current level of the antifreeze agent in the heat transfer fluid including i) adding further antifreeze agent to the heat transfer fluid when the current level is a predetermined amount lower than the wanted level, and ii) removing an amount of the antifreeze agent from the heat transfer fluid when the current level is a predetermined amount higher than the wanted level, wherein said determining step further comprises determining the wanted level of the antifreeze agent further based on long-term statistics over relations between the monitored incoming air temperature, previously chosen levels of the antifreeze agent associated with the monitored temperature of the incoming air, and a resulting temperature of the heat transfer fluid for a local installation, the long-term statistics being based on actual monitored incoming air temperature values and the monitored resulting temperature of the heat transfer fluid for the local installation in the operation of the heat exchange system of the ventilation system. ### Claim 2 (depends on 1) The method according to claim 1, wherein said determining step further comprises determining the wanted level of the antifreeze agent further based on long-time changes of the temperature of the incoming air. ### Claim 3 (depends on 1) The method according to claim 1, wherein said determining step further comprises determining the wanted level of the antifreeze agent further based on a temperature forecast from an external source. ### Claim 4 (depends on 1) The method according to claim 1, wherein said determining step further comprises determining the wanted level of the antifreeze agent further based on a temperature forecast from an external source. ### Claim 5 (depends on 1) The method according to claim 1, wherein said controlling step controls the current level of the antifreeze agent in the heat transfer fluid by the adding of the further antifreeze agent to the heat transfer fluid when the current level is the predetermined amount lower than the wanted level, the wanted level based on avoiding freezing of the heat transfer fluid based on the monitored temperature of the incoming air and a freezing point of the heat transfer fluid. ### Claim 6 (depends on 1) The method according to claim 1, wherein said controlling step controls the current level of the antifreeze agent in the heat transfer fluid by i) the adding of the further antifreeze agent to the heat transfer fluid when the current level is the predetermined amount lower than the wanted level, and ii) the removing of the amount of the antifreeze agent from the heat transfer fluid when the current level is the predetermined amount higher than the wanted level, the wanted level based on avoiding freezing of the heat transfer fluid based on the monitored temperature of the incoming air, a freezing point of the heat transfer fluid, and maximizing heat transfer efficiency of the heat transfer fluid. ### Claim 7 A heat exchange system (200) of a ventilation system configured to deliver heat to incoming air by outgoing air heating a heat transfer fluid, for the heat transfer fluid to transfer the heat to warm incoming air, a level of an antifreeze agent in the heat transfer fluid being dependent on a temperature of the incoming air, the system comprising: a heat collector unit (225) configured to collect the heat from the outgoing air; a heat deliver unit (230) configured to deliver the heat collected from the outgoing air to the incoming air, the heat collector unit and the heat deliver unit in fluid communication with each other; a separator (250) adapted to separate and remove an amount of the antifreeze agent from the heat transfer fluid; a remixer (245) adapted to add a part of the antifreeze agent to the heat transfer fluid; a first temperature sensor (275) configured to monitor the temperature of the incoming air, the first temperature sensor located upstream of the heat delivery unit (230); a second temperature sensor (280) configured to monitor a temperature of the heat transfer fluid; and a control unit (285) operatively connected with the separator (250), the remixer (245), and the first and second temperature sensors (275, 280), the control unit adapted to analyse current temperature data provided by the first and second temperature sensors (275) and to selectively order i) the separator to remove the amount of the antifreeze agent from the heat transfer fluid, and ii) the remixer to add the part of the antifreeze agent to the heat transfer fluid, based on the analysis of the current temperature data, wherein the heat collector unit i) delivers heat to incoming air by outgoing air heating the heat transfer fluid, and ii) transfers the heat from the heat transfer fluid to transfer to warm incoming air, wherein the control unit, in the analysis of the current temperature data, is adapted to further analyse long-term statistics over relations between the monitored incoming air temperature, previously chosen levels of the antifreeze agent associated with the monitored temperature of the incoming air, and a resulting temperature of the heat transfer fluid for a local installation, the long-term statistics being based on actual monitored incoming air temperature values and the monitored resulting temperature of the heat transfer fluid for the local installation in the operation of the heat exchange system of the ventilation system. ### Claim 8 (depends on 7) The heat exchange system of claim 7, wherein the control unit comprises an external communication unit for receiving at least one of external temperature and weather forecasts, the received at least one of the external temperature and the weather forecasts being used in the analysis of the current temperature data. ### Claim 9 (depends on 7) The heat exchange system according to claim 7, wherein said control unit controls a current level of the antifreeze agent in the heat transfer fluid by ordering the remixer to add the part of the antifreeze agent to the heat transfer fluid when the current level is a predetermined amount lower than a wanted level, the wanted level based on avoiding freezing of the heat transfer fluid based on the monitored temperature of the incoming air. ### Claim 10 (depends on 7) The heat exchange system according to claim 7, wherein said control unit controls the current level of the antifreeze agent in the heat transfer fluid by i) ordering the the remixer to add the part of the antifreeze agent to the heat transfer fluid when the current level is a predetermined amount lower than a wanted level, and ii) ordering the separator to remove the amount of the antifreeze agent from the heat transfer fluid when the current level is a predetermined amount higher than the wanted level, the wanted level based on avoiding freezing of the heat transfer fluid based on the monitored temperature of the incoming air while maximizing heat transfer efficiency of the heat transfer fluid. ### Claim 11 (depends on 9) The heat exchange system according to claim 9, wherein the wanted level is based on avoiding freezing of the heat transfer fluid based on i) the monitored temperature of the incoming air and ii) a freezing point of the heat transfer fluid. ### Claim 12 (depends on 10) The heat exchange system according to claim 10, wherein the wanted level is further based on a freezing point of the heat transfer fluid. ### Claim 13 A heat exchange system (200) of a ventilation system configured to deliver heat to incoming air by outgoing air heating a heat transfer fluid, for the heat transfer fluid to transfer the heat received from the outgoing air to warm incoming air, a level of an antifreeze agent in the heat transfer fluid being regulated dependent on a temperature of the incoming air, the system comprising: a heat collector unit (225) located with an outgoing air duct and configured to collect the heat from the outgoing air; a heat deliver unit (230) located in an incoming air duct and configured to deliver the heat collected from the outgoing air to the incoming air, the heat collector unit and the heat deliver unit in fluid communication with each other; a separator (250) connected to the heat deliver unit and adapted to separate and remove an amount of the antifreeze agent from the heat transfer fluid; a remixer (245) connected to the separator and to the heat collector unit, the remixer adapted to add a part of the antifreeze agent removed from by the separator back into the heat transfer fluid; a first temperature sensor (275) configured to monitor the temperature of the incoming air, the first temperature sensor located upstream of the heat delivery unit (230); a second temperature sensor (280) configured to monitor a temperature of the heat transfer fluid; and a control unit (285) operatively connected with the separator (250), the remixer (245), and the first and second temperature sensors (275, 280), the control unit adapted to analyse current temperature data provided by the first and second temperature sensors (275) and order i) the separator to remove the amount of the antifreeze agent from the heat transfer fluid, and ii) the remixer to add the part of the antifreeze agent to the heat transfer fluid, based at on the analysis of the current temperature data, wherein the heat collector unit i) delivers heat to incoming air by outgoing air heating the heat transfer fluid, and ii) transfers the heat from the heat transfer fluid to transfer to warm incoming air, wherein said control unit controls a current level of the antifreeze agent in the heat transfer fluid by ordering the remixer to add the part of the antifreeze agent to the heat transfer fluid when the current level is a predetermined amount lower than a wanted level, the wanted level based on avoiding freezing of the heat transfer fluid based on the monitored temperature of the incoming air, and wherein the wanted level is based on avoiding freezing of the heat transfer fluid based on i) the monitored temperature of the incoming air, ii) a freezing point of the heat transfer fluid, and iii) the monitored temperature of the heat transfer fluid, wherein the control unit, in the analysis of the current temperature data, is adapted to further analyse long-term statistics over relations between the monitored incoming air temperature, previously chosen levels of the antifreeze agent associated with the monitored temperature of the incoming air, and a resulting temperature of the heat transfer fluid for a local installation the long-term statistics being based on actual monitored incoming air temperature values and the monitored resulting temperature of the heat transfer fluid for the local installation in the operation of the heat exchange system of the ventilation system. ### Claim 14 (depends on 13) The heat exchange system according to claim 13, wherein the wanted level is based on avoiding freezing of the heat transfer fluid based while maximizing heat transfer efficiency of the heat transfer fluid.