# US 9,518,765 B2 · System and method for controlling temperature and humidity in multiple spaces using liquid desiccant > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,518,765 B2 - Document ID: US9518765B2 - Status: Granted - Kind: B2 - Application number: 14/022,381 - Filed: 2013-09-10 - Published: 2015-03-12 - Granted: 2016-12-13 - Earliest claimed: 2013-09-10 - Assignees: Mitsubishi Electric Research Laboratories, Inc. - Applicants: Mitsubishi Electric Research Laboratories, Inc. - Inventors: Christopher Laughman; Daniel J Burns; Scott A. Bortoff; Richard C. Waters - Web page: https://patentgrep.com/patent/US9518765B2 ## CPC - F25B 15/00: Sorption machines, plants or systems, operating continuously, e.g. absorption type - F24F 3/065: {with a plurality of evaporators or condensers} - F24F 3/1417: {with liquid hygroscopic desiccants} - F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP 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) ## Abstract A branch controller operates with a system for temperature and humidity control. The branch controller includes a fluid control system for controlling a flow of the liquid desiccant in an arrangement of channels forming a first path for exchanging the liquid desiccant between a liquid desiccant conditioning unit and at least a first space conditioning unit and a second path for directing the liquid desiccant received from the first space conditioning unit to a second space conditioning unit. The branch controller includes a processor for comparing operational conditions of the first space conditioning unit and the second space conditioning unit. The processor selects between the first path and the second path based on the comparison and commands the fluid control system to control the flow of the liquid desiccant according to the selected path. ## Claims ### Claim 1 A branch controller of a system for temperature and humidity control, the system including a liquid desiccant conditioning unit for changing a temperature and a concentration of a liquid desiccant and a plurality of space conditioning units for controlling the temperature and the humidity in a plurality of spaces using the liquid desiccant, the branch controller comprising: a fluid control system for controlling a flow of the liquid desiccant in an arrangement of channels forming a first path for exchanging the liquid desiccant between the liquid desiccant conditioning unit and at least a first space conditioning unit and a second path for directing the liquid desiccant, received by the first space conditioning unit from the liquid desiccant conditioning unit, from the first space conditioning unit to a second space conditioning unit; and a processor for comparing operational conditions of the first space conditioning unit and the second space conditioning unit, for selecting between the first path and the second path based on the comparison and for commanding the fluid control system to control the flow of the liquid desiccant according to the selected path, wherein comparing the operational conditions includes comparing at least one of sensible loads and latent loads of the first and the second space conditioning units, wherein the sensible load of each space conditioning unit includes a temperature difference between a current and a requested temperature in a space controlled by each space conditioning unit, and wherein the latent load of each space conditioning unit includes a humidity difference between a current and a requested humidity in the space controlled by each space conditioning unit. ### Claim 2 (depends on 1) The branch controller of claim 1, further comprising: a housing enclosing the processor and at least part of the fluid control system. ### Claim 3 (depends on 1) The branch controller of claim 1, wherein comparing the operational conditions includes comparing latent loads of the first and the second space conditioning units. ### Claim 4 (depends on 1) The branch controller of claim 1, wherein the processor determines the sensible load or the latent load of the first space conditioning unit based on the liquid desiccant received from the first space conditioning unit. ### Claim 5 (depends on 1) The branch controller of claim 1, further comprising: at least one heat exchanger for changing a temperature of the liquid desiccant received from the first space conditioning unit before redirecting the liquid desiccant in the second direction. ### Claim 6 (depends on 5) The branch controller of claim 5, further comprising: a plurality of heat exchangers including one heat exchanger for each space conditioning unit operatively connected to the branch controller. ### Claim 7 (depends on 5) The branch controller of claim 5, further comprising: a secondary fluid control system for controlling flow of secondary fluid into the heat exchanger for a thermal interaction with the liquid desiccant. ### Claim 8 (depends on 5) The branch controller of claim 5, wherein the liquid desiccant conditioning unit uses secondary fluid for reconditioning the liquid desiccant, and wherein the heat exchanger receives at least part of the secondary fluid for a thermal interaction with the liquid desiccant. ### Claim 9 (depends on 1) The branch controller of claim 1, wherein the branch controller is mechanically interconnected by the arrangement of channels with the liquid desiccant conditioning unit and the plurality of space conditioning units, wherein the arrangement of channels includes a channel mechanically connecting the first and the second space conditioning units and enabling the branch controller to direct the liquid desiccant received from the first space conditioning unit to the second space conditioning unit using the channel. ### Claim 10 (depends on 9) The branch controller of claim 9, wherein the fluid control system directs the liquid desiccant received from the first space conditioning unit to the second space conditioning unit through the channel without changing the concentration of the liquid desiccant. ### Claim 11 (depends on 1) The branch controller of claim 1, wherein the processor analyzes a concentration of the liquid desiccant received from the first space conditioning unit and, based on a result of the analysis, directs the liquid desiccant to the second space conditioning unit without changing the concentration of the liquid desiccant or, based on a result of the analysis, directs the liquid desiccant to the liquid desiccant conditioning unit for changing the concentration of the liquid desiccant. ### Claim 12 (depends on 1) The branch controller of claim 1, wherein the processor compares latent loads of the first and the second space conditioning units, and wherein the processor, in response to determining that the first space conditioning unit has a higher latent load than a latent load of the second space conditioning unit, directs, first, the liquid desiccant to the first space conditioning unit and directs, second, the liquid desiccant processed by the first space conditioning unit to the second space conditioning unit. ### Claim 13 A system for temperature and humidity control, comprising: a liquid desiccant conditioning unit for changing a temperature and a concentration of a liquid desiccant; a first space conditioning unit for controlling a first environment using the liquid desiccant; a second space conditioning unit for controlling a second environment using the liquid desiccant, wherein the liquid desiccant conditioning unit, the first space conditioning unit and the second space conditioning unit are interconnected with an arrangement of channels suitable for passing the liquid desiccant; and a branch controller for channeling the liquid desiccant received processed by the first space conditioning unit to either the liquid desiccant conditioning unit or the second space conditioning unit, wherein the branch controller includes a processor for comparing operational conditions of the first space conditioning unit and the second space conditioning unit, for selecting between the first path and the second path based on the comparison and for commanding the fluid control system to control the flow of the liquid desiccant according to the selected path, wherein comparing the operational conditions includes comparing at least one of sensible loads and latent loads of the first and the second space conditioning units, wherein the sensible load of each space conditioning unit includes a temperature difference between a current and a requested temperature in a space controlled by each space conditioning unit, and wherein the latent load of each space conditioning unit includes a humidity difference between a current and a requested humidity in the space controlled by each space conditioning unit. ### Claim 14 (depends on 13) The system of claim 13, wherein the branch controller includes a heat exchanger for changing the temperature of the liquid desiccant received from the first space conditioning unit before redirecting the liquid desiccant to the second space conditioning unit. ### Claim 15 (depends on 13) The system of claim 13, further comprising: a reservoir connected to the liquid desiccant conditioning unit for storing the concentrated liquid desiccant. ### Claim 16 (depends on 13) The system of claim 13, wherein the liquid desiccant conditioning comprises: a first heat exchanger for heating the liquid desiccant in a diluted state using secondary fluid at a high temperature to change the concentration of the liquid desiccant and to reduce a temperature of the secondary fluid to a low temperature; a second heat exchanger for cooling the liquid desiccant in a concentrated state using a first part of the secondary fluid at the low temperature; and wherein the branch controller comprises: a fluid control system for controlling a flow of the liquid desiccant in the arrangement of channels; a processor for comparing operational conditions of the first space conditioning unit and the second space conditioning unit to determine a direction of a flow of the liquid desiccant; and a heat exchanger for cooling the liquid desiccant received from the first space conditioning unit before redirecting the liquid desiccant to the second space conditioning unit using a second part of the secondary fluid at the low temperature received from the liquid desiccant conditioning unit. ### Claim 17 A method for controlling temperature and humidity in multiple spaces using a liquid desiccant, comprising: comparing an operational condition of a first space conditioning unit arranged for controlling a first environment using the liquid desiccant with an operational condition of a second space conditioning unit arranged for controlling a second environment using the liquid desiccant, wherein comparing the operational conditions includes comparing at least one of sensible loads and latent loads of the first and the second space conditioning units, wherein the sensible load of each space conditioning unit includes a temperature difference between a current and a requested temperature in a space controlled by each space conditioning unit, and wherein the latent load of each space conditioning unit includes a humidity difference between a current and a requested humidity in the space controlled by each space conditioning unit; selecting, in response to the comparing, between a first path for directing the liquid desiccant received from the first space conditioning unit to a liquid desiccant conditioning unit and a second path for directing the liquid desiccant received from the first space conditioning unit to a second space conditioning unit; and directing a flow of the liquid desiccant according to the selected path. ### Claim 18 (depends on 17) The method of claim 17, further comprising: changing a temperature of the liquid desiccant without changing a concentration of the liquid desiccant before directing the liquid desiccant according to the second path. ### Claim 19 (depends on 17) The method of claim 17, wherein the comparing includes comparing latent loads of the first and the second space conditioning units, further comprising: directing, first, the liquid desiccant to the first space conditioning unit having a higher latent load than a latent load of the second space conditioning unit, and directs, second, the liquid desiccant to the second space conditioning unit.