A refrigeration unit includes an evaporator circulating a flow of refrigerant therethrough to cool a flow of compartment air flowing over the evaporator, a compressor in fluid communication with the evaporator to compress the flow of refrigerant, an engine operably connected to the compressor to drive operation of the compressor, an expansion device in fluid communication with the flow of refrigerant, and a controller operably connected to at least the engine and the expansion device. The controller is configured to determine an available power to drive the compressor, determine a compressor discharge pressure upper limit based on the available power, compare the compressor discharge pressure upper limit to a requested compressor discharge pressure, and initiate adjustment of the expansion device such that an actual compressor discharge pressure is the lesser of the requested compressor discharge pressure or the compressor discharge pressure upper limit.

A refrigeration apparatus comprises a first refrigerant system and a second refrigerant system. The first refrigerant system comprises a first compressor, a cascade heat exchanger and a first evaporator. The second refrigerant system comprises a second compressor, a second condenser, the cascade heat exchanger and a second evaporator. The second compressor has an economizer port, and the cascade heat exchanger is connected to the economizer port of the second compressor.

A free cooling system includes a plurality of free cooling outdoor units each including a heat medium circuit, a controller, and a communication unit, the heat medium circuit being configured by connecting a heat medium pump, a first heat exchanger, and a heat source side of a second heat exchanger by pipes, a heat medium circulating in the heat medium circuit, the controller configured to control the heat medium pump, and the communication units performing communication with each other, wherein the plurality of free cooling outdoor units are coupled with each other by a load pipe that allows a load heat medium to flow to or flow out from a load side of each second heat exchanger.

Chiller control systems and methods for chiller control use iterative modeling of cooling towers, heat exchangers, and pumps to determine the feasibility of integrated free cooling and the ability to take advantage of free cooling. The control systems and control methods can further include selecting the parameters for operating in the free cooling or integrated free cooling mode to improve efficiency and/or reduce energy consumption when operating in these modes. The models can have inputs and outputs that feed into one another, and converge at a solution over multiple iterations. The feasibility of integrated free cooling can be based on providing cooling to a cooling load process fluid at a heat exchanger. The availability of free cooling can be based on the cooling provided at the heat exchanger achieving a target temperature for the cooling load process fluid.

A thermal management system includes a heat rejection device configured to fluidly couple to a refrigeration system, a fan configured to provide an entering airflow across the heat rejection device to cool a flow of water within the heat rejection device, and a controller configured to control a speed of the fan based on at least two of (i) a relative humidity of the entering airflow, (ii) a percentage of capacity one or more components of the refrigeration system are operating at, (iii) a ratio of water to energy costs, and (iv) a ratio of a design power of a compressor of the refrigeration system to a design power of the fan to minimize a total utility operation cost of the thermal management system including (i) energy costs to operate the fan and the refrigeration system and (ii) water costs of the flow of water.

An apparatus for staged startup of air-cooled low charged packaged ammonia refrigeration system includes motorized valves on condenser coil inlets, a main compressor discharge motorized valve, a bypass pressure regulator valve in the main compressor piping, and check valves on the condenser outlets. The condenser inlet motorized valves provide precise control of gas feed to the condensers, so pressure can build without collapsing oil pressure. The condenser outlet contains check valves to prevent liquid backflow during coil isolation. The compressor discharge line contains a motorized valve for regulating discharge pressure at start-up. The motorized valve in the compressor discharge piping includes a bypass with a pressure regulator for precise regulation at minimum discharge pressure. Once discharge pressure rises above the setpoint, the condenser inlet solenoid coils open one at a time. The discharge pressure regulating motorized valve simultaneously regulates the discharge pressure until the condenser maintains discharge pressure.

An augmented heat transfer system can be used to control the humidity of adjacent conditioned spaces by selectively absorbing latent heat energy from a relatively warm space, such as a loading dock, and discharging this energy in the form of sensible heat to an adjacent relatively cold space, such as a freezer served by the loading dock. This transfer of sensible heat energy into the cold space induces a vapor compression system to remove sufficient moisture from the cold space to avoid uncontrolled precipitation. At the same time, the process of removing moisture/latent heat from the warm space can also be used to reduce humidity in the warm space via condensation on a cold evaporator. Therefore, in operations where the warm space and the cold space are both nominally sealed from ambient air, such as an indoor loading dock serving a freezer, the augmented heat transfer system can eliminate uncontrolled precipitation in the freezer while also mitigating moisture ingress to the freezer from the dock space.

This present application relates to a portable consumer convenience appliance that uses refrigeration coils to cool or freeze a consumer food product. The appliance of the present invention has an outer supporting base and an inner removable container made from ceramic. The outer base has an integrated refrigeration unit, and the inner container may be filled with a food or beverage. The refrigeration coils of the integrated refrigeration unit are used to chill or freeze the food or beverage stored in the inner container until consumed.

A heat transfer system for controlling two or more heat loads, including a high transient heat load, is provided. The heat transfer system may include sensible-heat thermal energy storage. A method of transferring heat from two or more heat loads to an ambient environment is further provided.

A condenser (404) configured to condense gas phase refrigerant to liquid phase refrigerant. The condenser (404) includes a gas header (408) configured to receive gas phase refrigerant, a liquid header (410) disposed opposite the gas header, the liquid header (410) separated into at least two sections, each section of the at least two sections having a port, and parallel tubes (406) extending between the gas header (408) and the liquid header (410).