US 5,395,042 AGranted

Apparatus and method for automatic climate control

AssigneeSmart Systems International

InventorsJoseph D. Riley, Marc H. Popek

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Abstract

An apparatus and method for controlling the operation of (HVAC) equipment or other climate control equipment. The method is executed by a conventional computer with a memory storing a program. The system determines whether the space is not occupied and if the temperature drifts outside an allowed margin, then the system allows the temperature to drift to a maximum allowable margin, or to a newly determined margin, whichever is less. The newly determined margin is based upon a determination of the maximum temperature margin to which the system can drift and still drive the temperature back substantially to the use set point within a predetermined maximum recovery time. The recovery time is calculated based upon past temperature-vs.-time data stored for previous cycles of drift and drive. The system can further increase the energy savings by augmenting the allowed recovery time and/or maximum drift range when the ratio of the incremental drift time to the consequent required drive time exceeds a predetermined, programmable amount, i.e. when the added drive time required to return to a certain temperature is small relative to the added allowed drift time for the space, during which the HVAC equipment is not operating and hence no energy is being consumed. Savings and usage of energy over time are stored, and are output to the user upon request to the control computer. The stored data can also be used to determine whether the HVAC equipment's efficiency is deteriorating, and thus whether corrective maintenance is needed.

Claims47

Dependent claims

An apparatus for governing levels of an environmental attribute of a room by controlling operation of an environmental control unit for affecting said levels of said attribute of the room, said apparatus including an interface coupled to said environmental control unit to controlling the operation thereof by control signals, the apparatus comprising:

a controller including a processor coupled to a memory, the memory storing an environmental control program including program instructions for controlling said operation of said environmental control unit by generating said control signals and further storing data including a first drift relationship, a first drive relationship, a predetermined set point representing a predetermined level of said attribute, a predetermined maximum range relative to said set point, a predetermined minimum range relative to said set point and a predetermined maximum recovery time, the controller further including a timer coupled to said processor for timing events related to said environmental control, said events including generation of said control signals and reception of signals representing said levels within said room;
an input device coupled to said controller for inputting at least one of said predetermined set point, maximum range, minimum range and recovery time;
an environmental attribute sensor coupled to said controller for providing, at any given time, one said signal representing the level of said attribute within the room;
and
an occupancy sensor coupled to said controller for determining whether the room is occupied, and for sending a said control signal to the controller to take one of a first action and a second action, the first action being taken if the room is unoccupied to allow said level in the room to drift towards an ambient level of said attribute in a region adjacent the room and the second action being taken if the room is occupied to operate said environmental control unit to drive said attribute level in the room away from said ambient level;
wherein the environmental control program includes instructions to allow said drift only to said maximum range when the space is unoccupied, and then, when reoccupied, to activate the environmental control unit for driving the attribute level in the room towards a target level of said attribute within said minimum range of said set point;
and
wherein said maximum range is limited such that an amount of drive time for said environmental control unit to drive said attribute level in the room from said maximum range to said target level of said attribute is no greater than said predetermined maximum recovery time.

5 more elements

A method for controlling levels of an environmental attribute of a room, the method being executed by a program having instructions stored in the memory of a computer controlling the operation of an environmental control unit for affecting said levels of said attribute, the method including the steps of:

(1) storing a set point representing a predetermined level of said attribute in said memory, a predetermined margin around said predetermined level, a maximum allowed drift deviation for when the room is unoccupied, a minimal drift deviation, and a maximum allowed recovery time to recover to said minimal drift deviation;
(2) determining whether said room is occupied;
(3) determining a current level of said attribute in said room;
(4) determining whether said current level is within said margin of said predetermined level;
and if not, then proceeding to step 5, but if so, then stopping the operation of the environmental control unit if it is operating, and proceeding to step 2;
(5) if the determination of step 2 is positive, then proceeding to step 6, and otherwise proceeding to step 7;
(6) operating said environmental control unit to drive said current level towards said predetermined level, and then proceeding to step 2;
(7) setting a dynamic deviation of said attribute from said predetermined level to be the smaller of said maximum allowed drift deviation and a new allowed drift deviation for which the time to recover to said minimal drift deviation by operating said environmental control unit is no greater than said maximum allowed recovery time;
(8) determining whether said current level is within said dynamic deviation of said predetermined level of said attribute, and if not, then:
(8A) proceeding to step 6;
but if so, then:
(8B) stopping the operation of the environmental control unit if it is operating and then proceeding to step 2;
for allowing said current level to drift further from said predetermined level when said room is unoccupied but enabling recovery to said predetermined level within said maximum recovery time.

10 more elements

Dependencies are inferred from the claim text.