TECHNICAL FIELD

The present disclosure relates generally to heating, ventilation, and air conditioning (HVAC) systems and methods of their use. In certain embodiments, the present disclosure relates to peak demand response operation with improved sensible capacity.

BACKGROUND

Heating, ventilation, and air conditioning (HVAC) systems are used to regulate environmental conditions within an enclosed space. Air is cooled via heat transfer with refrigerant flowing through the HVAC system and returned to the enclosed space as conditioned air.

SUMMARY OF THE DISCLOSURE

In an embodiment, an HVAC system includes a variable-speed compressor configured to compress refrigerant flowing through the HVAC system, a blower configured to provide a flow of air through the HVAC system at a controllable flow rate, and a controller communicatively coupled to the variable-speed compressor and the blower. The controller receives a demand request, which includes a command to operate the HVAC system at a predefined setpoint temperature. In response to receiving the demand request, a setpoint temperature associated with the HVAC system is adjusted to the predefined setpoint temperature. The variable-speed compressor is adjusted to a low-speed setting, thereby operating the HVAC system at a first tonnage of cooling corresponding to the decreased speed of the variable-speed compressor. The rate of the flow of air provided by the blower is adjusted to a first flow rate, such that a ratio of the first flow rate to the first tonnage of cooling is increased to a first predefined value.

In another embodiment, an HVAC system includes a variable-speed compressor configured to compress refrigerant flowing through the HVAC system, a blower configured to provide a flow of air through the HVAC system at a controllable flow rate, and a controller communicatively coupled to the variable-speed compressor and the blower. The controller is configured to receive a demand request, which includes a command to operate the HVAC system at a predefined setpoint temperature. In response to receiving the demand request, a setpoint temperature associated with the HVAC system is adjusted to the predefined setpoint temperature. A speed of the variable-speed compressor is decreased to a low-speed setting. Based on the decreased speed of the variable-speed compressor, an air-flow rate is determined to provide by the blower. The controllable flow rate of the flow of air provided by the blower is adjusted based on the determined air-flow rate.

In yet another embodiment, an HVAC system includes a cooling unit with a face-split evaporator. The face-split evaporator includes a top evaporator circuit positioned above a bottom evaporator circuit. The top evaporator circuit is configured to transfer heat from a first portion of a flow of air passing across the top evaporator circuit to refrigerant in the top evaporator circuit. The bottom evaporator circuit is configured to transfer heat from a second portion of the flow of air passing across the bottom evaporator circuit to refrigerant in the bottom evaporator circuit. The system further includes a first compressor associated with the top evaporator circuit and configured to compress refrigerant received from the top evaporator circuit, a second compressor associated with the bottom evaporator circuit and configured to compress refrigerant received from the bottom evaporator circuit, and a controller communicatively coupled to the first compressor and the second compressor. The controller receives a demand request, which includes a command to reduce power consumption by the HVAC system by a predefined percentage. In response to receiving the demand request, the second compressor is turned off to inactivate the bottom evaporator circuit such that power consumption by the HVAC system is decreased by at least the predefined percentage associated with the demand request. A first portion of a liquid condensate formed on a surface of the top evaporator circuit is allowed to fall on a surface of the bottom evaporator circuit such that the second portion of the flow of air is evaporatively cooled by the first portion of the liquid condensate.

In some cases, HVAC systems may be required to operate under restricted operating requirements to reduce power consumption during times of peak electricity demand, referred to in this disclosure as peak demand response times. For example, a third party such as a utility provider may enforce certain operating restrictions upon HVAC systems during peak demand response times. A peak demand response time may correspond, for example, to a time period associated with high outdoor temperatures or any other time when electrical power consumption is expected (e.g., based on a forecast or projection) to be increased. Generally, the third party (e.g., a utility provider) provides a command request which specifies either a setpoint temperature or a reduction of power consumption at which an HVAC system should operate during a peak demand response time. In some cases, the demand request may be provided via an electronic signal. The demand request may be transmitted to a controller of the HVAC system to communicate operating requirements that are to be enforced during a peak demand response time.

The unconventional HVAC systems contemplated in the present disclosure solve problems of previous systems by facilitating improved cooling during a peak demand response time (e.g., by increasing sensible capacity during the peak demand response time). The present disclosure encompasses the recognition that the sensible capacity of HVAC systems may be increased during peak demand response times by temporarily modifying operating parameters of the HVAC system to improve comfort in a conditioned space while still satisfying the requirements of a demand request. For example, a speed of a compressor of the HVAC system may be temporarily decreased to increase a sensible heat ratio of the HVAC system and improve the sensible capacity of the HVAC system during a peak demand response time. In this way the HVAC system may continue to effectively cool a space while still satisfying requirements of a demand request (e.g., to increase a setpoint temperature or reduce power consumption by a given percentage). In some embodiments, the systems and methods described in this disclosure are configured to exploit the benefits of evaporative cooling to provide improved sensible capacity, and thereby provide more comfortable temperatures during peak demand response times than was possible using previous technologies. Moreover, the systems and methods described in this disclosure may be integrated into a practical application for improving the performance and sensible cooling capacity of HVAC systems during peak demand response times.

Certain embodiments may include none, some, or all of the above technical advantages. One or more other technical advantages may be readily apparent to one skilled in the art from the figures, descriptions, and claims included herein.

