Abstract: A method for estimating a heating/cooling load of a zone within a building may include determining a measured parameter from the zone, generating a reduced order thermodynamic model of the zone, generating an Extended Kalman Filter based on the thermodynamic model of the zone, and processing the measured parameter using the Extended Kalman Filter to estimate at least one unknown state of the zone, such as an estimated load. A similar method may be used to estimate a temperature in a cold room of a refrigeration system.

Abstract: A method for estimating a heating/cooling load of a zone within a building may include determining a measured parameter from the zone, generating a reduced order thermodynamic model of the zone, generating an Extended Kalman Filter based on the thermodynamic model of the zone, and processing the measured parameter using the Extended Kalman Filter to estimate at least one unknown state of the zone, such as an estimated load. A similar method may be used to estimate a temperature in a cold room of a refrigeration system.

Abstract: A method and system for operating a CO2 refrigeration system is provided. Two pressures are controlled by two controllers through two valves in this system. A first valve is actuated by a first controller using a first transfer function in response to the first measured pressure. A second valve is actuated by a second controller using a second transfer function in response to the second measured pressure. When it is determining the second valve failed to operate correctly, the first valve is actuated by a third controller using a third transfer function.