Abstract: A humidity control method is provided for a multi-stage cooling system having two or more refrigerant circuits. A hot gas re-heat circuit having a hot gas re-heat coil, an evaporator and a compressor, such as the evaporator and compressor utilized in one of the refrigerant circuits, is provided. The hot gas re-heat coil is placed in fluid communication with the output airflow from the evaporator of the re-heat circuit. Humidity control is performed during cooling operations and ventilation operations. During a first stage cooling operation using only one refrigerant circuit and having a low cooling demand, the request for humidity control activates the hot gas re-heat circuit for dehumidification and activates a second refrigerant circuit to provide cooling capacity. During a second stage cooling operation using multiple refrigerant circuits and having a high cooling demand, the request for humidity control is suspended until completion of the second stage cooling demand.

Abstract: A method and system is provided for gathering and packetizing data from networked building automation equipment, and for transmitting data packets as instant messages to remotely located users. An instant messaging (IM) server-based system is provided to facilitate communication between networked building equipment and a remotely located service contractor. When a registered router is operated, the router establishes a continuous pass-through communication link with the IM server and with building equipment connected to the router. The router automatically polls connected building equipment for alarms, faults and system failures, and also receives, processes, and responds to user requests for specific data from particular items of building equipment. Data gathered by the router is packetized, and the packets are then encapsulated into an instant message that is transmitted to the IM server.

Abstract: A controller controls operation of a HVAC&R device, bringing the temperature inside a structure from a first temperature to a second temperature at a predetermined time each day. Sensors sense the temperature both inside and outside the structure. A recovery time is calculated based upon a previously calculated air treatment rate of temperature recovery for the HVAC&R device to drive the temperature of the structure through a temperature change, the recovery time calculation being obtained by multiplying the difference between the sensed temperature inside the structure and the second temperature by the previously calculated air treatment rate. A correction factor is calculated based upon a relationship between the sensed outside temperature and a previously sensed outside temperature, the correction factor being added to obtain a corrected recovery time. The HVAC&R device is initiated at a time defined by the predetermined time subtracted from the corrected recovery time.

Abstract: A humidity control method is provided for a multi-stage cooling system having two or more refrigerant circuits. A hot gas re-heat circuit having a hot gas re-heat coil is connected to one of the refrigerant circuits and is placed in fluid communication with the output airflow from the evaporator of that refrigerant circuit to provide additional dehumidification to the air. Humidity control is only performed during cooling operations and ventilation operations. During a first stage cooling operation using only one refrigerant circuit and having a low cooling demand, the request for humidity control activates the hot gas re-heat circuit for dehumidification and activates a second refrigerant circuit to provide cooling capacity. During a second stage cooling operation using two or more refrigerant circuits and having a high cooling demand, the request for humidity control is suspended and is initiated only upon the completion of the second stage cooling demand.

Abstract: An air inflatable mattress and mattress coverlet are provided for the prevention and treatment of decubitus ulcers (i.e., pressure sores or bedsores). The mattress incorporates a user selectable static or alternating air powered support surface for more uniformly redistributing pressure exerted on a patient's skin. The mattress coverlet encompasses a low air loss feature independent of the mattress's user selectable air powered support surface. Such low air loss feature provides a patient contact surface exhibiting a high moisture vapor transfer ratio in conjunction with a forced air flow to aid in reducing the moisture and heat near the patient's body. Both the mattress and mattress coverlet are driven by an external control system which houses the user controls, as well as the necessary pumps, regulators, and valving.

Abstract: A system and method is provided for an HVAC or refrigeration unit to obtain an appropriate address in order to commission the unit into a networked controls system. The units are assigned a predetermined address at the factory. After the unit is installed and is wired into the control network, a single action can be taken by an operator to commission the unit into the network. In commissioning the unit into the network, a valid address has to be obtained for the unit. A valid address is obtained for the unit by sequentially checking addresses on the network until an available address is located. Once an available address is located, the available address is assigned to the unit and the control system is notified of the address to commission the unit into the network.

Abstract: A humidity control method is provided for a multi-stage cooling system having two or more refrigerant circuits. A hot gas re-heat circuit having a hot gas re-heat coil is connected to one of the refrigerant circuits and is placed in fluid communication with the output airflow from the evaporator of that refrigerant circuit to provide additional dehumidification to the air. Humidity control is only performed during cooling operations and ventilation operations. During a first stage cooling operation using only one refrigerant circuit and having a low cooling demand, the request for humidity control activates the hot gas re-heat circuit for dehumidification and activates a second refrigerant circuit to provide cooling capacity. During a second stage cooling operation using two or more refrigerant circuits and having a high cooling demand, the request for humidity control is suspended and is initiated only upon the completion of the second stage cooling demand.

Abstract: A method of controlling an economizer is provided. A heating, ventilating, and air conditioning unit is operated in one of a heating mode and a cooling mode to provide conditioned air to a plurality of zones. A first temperature representative of air returned to the unit from the plurality of zones is sensed and a second temperature representative of the outdoor air is sensed. An economizer is modulated to increase the amount of outdoor air entering the unit when the first temperature falls below a cooling setpoint, the second temperature is greater than the first temperature, and the unit is operating in the cooling mode. The economizer is also modulated to increase the amount of outdoor air entering the unit when the first temperature rises above a heating setpoint, the second temperature is lower than the first temperature, and the unit is operating in the heating mode.

Abstract: A method and system for controlling the temperature of air returned to a conditioning unit in a zoned system is disclosed. The system includes a heating, ventilating, and air conditioning (HVAC) unit that has an economizer. The HVAC unit is connected to a plurality of zones by a supply duct and a return duct. A temperature sensor is provided to sense the temperature of air returning to the HVAC unit. A main control increases the amount of outdoor air entering the system through the economizer when the temperature of the returned air is excessively warm or excessively cold.

Abstract: A method and system for controlling the temperature of air returned to a conditioning unit in a zoned system is disclosed. The system includes a heating, ventilating, and air conditioning (HVAC) unit that has an economizer. The HVAC unit is connected to a plurality of zones by a supply duct and a return duct. A temperature sensor is provided to sense the temperature of air returning to the HVAC unit. A main control increases the amount of outdoor air entering the system through the economizer when the temperature of the returned air is excessively warm or excessively cold.