A state-based control system for an air handling unit (AHU) includes a finite state machine configured to transition between a high cooling load state and a low cooling load state. In the high cooling load state, the system maintains the temperature of a supply airstream provided by the AHU at a fixed setpoint and controls the temperature of a building zone by modulating the speed of a supply air fan. In the low cooling load state, the system operates the supply air fan at a fixed speed and controls the zone temperature by modulating an amount of cooling applied to the supply airstream by one or more cooling stages. A feed-forward module manages disturbances caused by adding or shedding cooling stages by applying a feed-forward gain to the supply air fan setpoint.

A system includes a converter and a controller to control a compressor and operates without receiving power supply from a thermostat. The converter receives a demand signal from the thermostat that is used to power the controller and charge a capacitor. When the thermostat de-asserts the demand signal, the charged capacitor powers the controller, which saves system parameters in a nonvolatile memory and enters a power save mode. The life of the nonvolatile memory is extended by alternately storing the system parameters in different memory locations. The system normalizes outdoor ambient temperature (OAT) during a demand cycle. The system determines OAT slope, which is used to select durations to operate the compressor at different capacities, by performing time based calculations during a demand cycle, demand cycle based calculations at the start of a demand cycle, or time and demand cycle based calculations during a demand cycle.

Techniques for providing an adaptive energy management system for responding to extreme weather conditions are described herein. In an embodiment, a server computer stores multiple policy datasets each representing HVAC control policy for different structure locations and one or more extreme weather conditions. The server computer receives weather condition data comprising a condition identifier of a then-current extreme weather condition in association with a location identifier specifying a particular geographical region. Based on the location identifier, a particular structure location, being within the particular geographic region, is identified. Based on the particular structure location, a particular policy dataset from among the policy datasets is identified. The particular policy dataset is transformed into HVAC equipment instructions, which the server computer transmits, over a network, to HVAC equipment at the particular structure location which, when executed, cause the HVAC equipment to execute an action in accordance with the particular policy dataset.

A method of controlling operation of an air conditioning system (10) includes measuring a compressor speed of one or more chillers (12) of an air conditioning system and measuring a refrigerant pressure of the one or more chillers of the air conditioning system. A chiller load is calculated using the compressor speed and the refrigerant pressure. An air conditioning system includes one or more chillers. Each chiller includes a compressor (22), a condenser (30) operably connected to the compressor, and an evaporator (28) operably connected to the compressor and the condenser. A controller (34) is operably connected to the one or more chillers and is configured to calculate a chiller load utilizing a measurement of compressor speed and a measurement of refrigerant pressure of the chiller.

A programmable thermostat supports at least one attribute where each different attribute values may support different sets of thermostatic settings. The programmable thermostat may be programmed based on the different attribute values rather than on temperature set points that are traditionally mapped to programmed times. Each set may include settings for a plurality of controlled equipment including a heating/cooling system, fan, ventilator, humidifier, and/or de-humidifier. Each embodiment may support attribute values associated with an occupancy attribute (which is indicative whether or not people are occupying an environmental entity) and/or a scenario attribute (which flexibly maps different thermostatic settings to different scenario attribute values). Stored configuration data about the thermostatic settings may be organized as a tree structure, where the leaves correspond to the thermostatic settings. A programmable thermostat/ventilator controller may also instruct a ventilator system to run during an adjustable pre-occupancy purge time duration before an environmental entity is occupied.

A first power consumption estimation unit estimates as a first power consumption, a power consumption generated in a first operation mode in which operation of an air conditioner is suspended at a timing when a room equipped with the air conditioner turns not to be used and the operation of the air conditioner is resumed so that a temperature of the room reaches a preset temperature at a timing when the room turns to be used. A second power consumption estimation unit estimates as a second power consumption, a power consumption generated in a second operation mode in which the operation of the air conditioner is continued even while the room is not being used. A determination unit compares the first power consumption with the second to determine whether to suspend or continue the operation of the air conditioner at the timing when the room turns not to be used.

Various embodiments of the teachings herein include a method of controlling a comfort parameter with a system comprising a user interface device, a sensor, and a control device, wherein the sensor measures a parameter different from the comfort parameter. The method may include: providing a demand signal requesting a change in the comfort parameter from a user using the user interface device; transmitting the demand signal from the user interface device to the control device; obtaining a reading from the sensor, the reading corresponding to a value of the parameter; analyzing the demand signal based on a current state of the system the reading obtained from the sensor; changing one or more settings of the system based on the analysis of the demand signal; and producing a control signal as a function of the one or more changed settings of the system.

An air-conditioning apparatus includes refrigerant systems that each include an outdoor unit and indoor units and that air-condition a single room, and circulators for making a temperature distribution in the room uniform. The air-conditioning apparatus determines a load on each of the two refrigerant systems in operation, and, if it is determined that improvement of operating efficiency is possible on the basis of the determination result, performs a system-selective operation in which operation of one of the refrigerant systems determined to be under a low load is stopped and the other refrigerant system determined to be under a high load is selectively performed, and causes the circulators to transport blown air blown from the indoor units of the refrigerant system determined to be under a high load to an air-conditioned zone of the refrigerant system determined to be under a low load.

The purpose of the present invention is to avoid frequent repetition of an increase/decrease stage caused by the inclusion, in a heat source system, of a machine the capacity of which has been degraded. A heat source system of the present invention is provided with a plurality of heat source machines. A higher-level control device (20) controls each of the heat source machines so that a heat medium delivery temperature, which is the temperature of a heat medium being supplied to an external load, will be a set temperature. The higher-level control device (20) is provided with a number-of-machines control unit (22), a degraded machine detection unit (24), and a priority ranking modification unit (25). The number-of-machines control unit (22) controls the number of heat source machines in accordance with operational priority ranking information in which each of the heat source machines and an operational priority ranking are associated together. The degraded machine detection unit (24) detects, as a capacity-degraded machine, a heat source machine that satisfies a predetermined capacity degradation condition, from among operating heat source machines. The priority ranking modification unit (25), if a capacity-degraded machine has been detected, modifies to a lowest position the operational priority ranking of the capacity-degraded machine in the operational priority ranking information.

An environmental control device (100, 200), such as a thermostat, is disclosed. The environmental control device (100, 200) has one or more terminals (104, 104a-104i) for connecting to an HVAC system (14) and performs over current management of the terminal (104, 104a-104i) when connected to the HVAC system (14).