Abstract: A system for a server room management includes an air-conditioning control device including: an acquisition unit; a setting unit that sets content for generating supply air at temperature, absolute humidity, and relative humidity within target range, based on outside air temperature and humidity as well as return air temperature; and a controller controlling amount of outside air, amount of return air, control amount of humidifier, control amount of cooler, and amount of air blown by blower, based on the content. If the outside air is within range greater than absolute humidity upper limit, or within range greater than enthalpy upper limit and greater than the temperature upper limit, the setting unit compares outside air and return air, and then determines, in accordance with the comparison, whether to set the content so that the cooler performs cooling by minimizing or maximizing the amount of the outside air.

Abstract: An HVAC system has two variable-air-volume (VAV) systems, a first VAV system for moving fresh air and a second VAV system for moving recycled air. Both the fresh air and recycled air are cooled and dehumidified by a single heat-exchanging coil. The fresh and recycled air streams travel independently in separate ducts until the air streams reach a remotely located mixing box where the air streams mix and ventilate into a room or zone of a building. The HVAC system uses carbon dioxide and temperature sensors in order to regulate the flow of fresh and recycled air to various mixing boxes throughout the building.

Abstract: A VAV air handler includes a cooling coil with a return air bypass damper for improved dehumidification. The bypass interjects into the supply air a portion of relatively warm, dry return air downstream of the cooling coil. This allows the cooling coil to absorb more latent heat from the incoming outside air and the remaining portion of the return air over a broad range of operating conditions, but especially at low load conditions.

Abstract: A method and an arrangement for controlling heat transfer in a ventilation apparatus or an air conditioning apparatus, in which heat contained in exhaust air is recovered into supply air by means of a heat transfer circuit having fluid circulation. Additional heating or additional cooling energy is supplied to the heat transfer circuit when the heat transfer is insufficient for maintaining a desired temperature of the supply air. To optimize the heat recovery, the supply of additional heating or cooling energy is minimized by measuring the temperatures and fluid flows of the heat transfer fluid and of the additional energy.