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This section presents methods and examples of computing the steady-state heating and cooling loads of aircraft compartments. In a steady-state process the flows of heat throughout the system are stabilized and thus do not change with time. In an aircraft compartment, several elements compose the steady-state air conditioning load. Transfer of heat occurs between these sources and sinks by the combined processes of convection, radiation, and conduction in the following manner: 1. Convection between the boundary layer and the outer airplane skin. 2. Radiation between the external skin and the external environment. 3. Solar radiation through transparent areas directly on flight personnel and equipment and on the cabin interior surfaces. 4. Conduction through the cabin walls and structural members. 5. Convection between the interior cabin surface and the cabin air. 6. Convection between cabin air and flight personnel or equipment. 7.

This document provides guidance for ECS design for UA primarily by reference to existing applicable SAE AC-9 documents with indication of how they would apply and how they may need to be adapted for UA. This document provides guidance related to environmental control for onboard equipment, cargo, animals, and passengers. This document cannot provide detail design guidance for all potential types of UA. Limited information is available for ECS requirements for UA that may carry passengers, but it should be expected that the same comfort and safety standards would be applied to UA as prescribed in current civil aviation authority rules and military specifications. Additional requirements unique to UA can be expected for totally autonomous UA operation with no provision for flight or ground crew monitoring and intervention in the event of ECS failures or malfunctions. This document does not pertain to the related ground stations that may be controlling the UA.

This SAE Aerospace Recommended Practice (ARP) describes a method of conducting an endurance test using contaminated air when the applicable specification requires non-recirculation of the contaminants. The objective of the test is to determine the resistance of the engine mounted components to wear or damage caused by the contaminated air. The method described herein calls for non-recirculation of the contaminants and is intended to provide a uniform distribution of the contaminant at the inlet to the Unit Under Test (UUT). The UUT may require the use of a hydraulic fluid for actuation of components within the test unit. Contamination of the test hydraulic fluid is not part of this recommended practice. If contaminated hydraulic fluid is required by the applicable test specification, refer to MAP749.

This ARP provides the definition of terms commonly used in aircraft environmental control system (ECS) design and analysis. Many of the terms may be used as guidelines for establishing standard ECS nomenclature. Some general thermodynamic terms are included that are frequently used in ECS analysis, but this document is not meant to be an inclusive list of such terms.

This SAE Aerospace Standard (AS) defines the requirements for air cycle air conditioning systems used on military air vehicles for cooling, heating, ventilation, and moisture and contamination control. General recommendations for an air conditioning system, which may include an air cycle system as a cooling source, are included in MIL-E-18927E and JSSG-2009. Air cycle air conditioning systems include those components which condition high temperature and high pressure air for delivery to occupied and equipment compartments and to electrical and electronic equipment. This document is applicable to open and closed loop air cycle systems. Definitions are contained in Section 5 of this document.

This SAE Aerospace Standard (AS) covers combustion heaters and accessories used in, but not limited to, the following applications: a Cabin heating (all occupied regions and windshield heating) b Wing and empennage anti-icing c Engine and accessory heating (when heater is installed as part of the aircraft) d Aircraft deicing

This SAE Aerospace Information Report (AIR) provides information on air quality and some of the factors affecting the perception of cabin air quality in commercial aircraft cabin air. Also a typical safety analysis process utilizing a Functional Hazard Assessment approach is discussed.

This Aerospace Information Report (AIR) is limited in scope to the general consideration of environmental control system noise and its effect on occupant comfort. Additional information on the control of environmental control system noise may be found in 2.3 and in the documents referenced throughout the text. This document does not contain sufficient direction and detail to accomplish effective and complete acoustic designs.

This SAE Aerospace Information Report (AIR) contains information on the thermal design requirements of airborne avionic systems used in military airborne applications. Methods are explored which are commonly used to provide thermal control of avionic systems. Both air and liquid cooled systems are discussed.

This Aerospace Information Report (AIR) outlines the design considerations and criteria for the control of water carryover from the environmental control system (ECS) with respect to causes and indicated corrective or preventative action. In addition, condensation on structure will be reviewed with possible preventative action described.

This SAE Aerospace Recommended Practice (ARP) contains guidelines and recommendations for subsonic airplane air conditioning systems and components, including requirements, design philosophy, testing, and ambient conditions. The airplane air conditioning system comprises that arrangement of equipment, controls, and indicators that supply and distribute air to the occupied compartments for ventilation, pressurization, and temperature and moisture control. The principal features of the system are: a A supply of outside air with independent control valve(s). b A means for heating. c A means for cooling (air or vapor cycle units and heat exchangers). d A means for removing excess moisture from the air supply. e A ventilation subsystem. f A temperature control subsystem. g A pressure control subsystem. Other system components for treating cabin air, such as filtration and humidification, are included, as are the ancillary functions of equipment cooling and cargo compartment conditioning.

The fluid flow treated in this section is isothermal, subsonic, and incompressible. The effects of heat addition, work on the fluid, variation in sonic velocity, and changes in elevation are neglected. An incompressible fluid is one in which a change in pressure causes no resulting change in fluid density. The assumption that liquids are incompressible introduces no appreciable error in calculations, but the assumption that a gas is incompressible introduces an error of a magnitude that is dependent on the fluid velocity and on the loss coefficient of the particular duct section or price of equipment. Fit 1A-1 shows the error in pressure drop resulting from assuming that air is incompressible.With reasonably small loss coefficients and the accuracy that is usually required in most calculations, compressible fluids may be treated as incompressible for velocities less than Mach 0.2.

Test Recommendations for Active and Passive Devices for Air Purification Devices for Aircraft Cabin Air Supplies for Commercial and Business Aircraft.

This document supplements ARP85, to extend its use in the design of ECS for supersonic transports. The ECS provides an environment controlled within specified operational limits of comfort and safety, for humans, animals and equipment. These limits include pressure, temperature, humidity, conditioned air velocity, ventilation rate, thermal radiation, wall temperature, audible noise, vibration, and composition (ozone, contaminants, etc.) of the environment. The ECS is comprised of equipment, controls, and indicators that supply and distribute conditioned air to the occupied compartments. This system is defined within the ATA 100 specification, Chapter 21. It interfaces with the pneumatic system (Chapter 36 of ATA 100), at the inlet of the air conditioning system shutoff valves.

This Recommended Practice is intended to outline the design, installation, testing, and field maintenance criteria for a high temperature metal pneumatic duct system, for use as a guide in the aircraft industry. These recommendations are to be considered as currently applicable and necessarily subject to revision from time to time, as a result of the rapid development of the industry.

This document deals with ground and flight test of airplane installed Environmental Control Systems (ECS), Figure 1. The ECS provide an environment, controlled within specified operational limits of comfort and safety, for humans, animals, and equipment. These limits include the following: pressure, temperature, humidity, ventilation air velocity, ventilation rate, wall temperature, audible noise, vibration, and environment composition (ozone, contaminants, etc.). The ECS are composed of equipment, controls, and indicators that supply, distribute, recycle and exhaust air to maintain the desired environment.

This SAE Aerospace Information Report (AIR) provides data and general analysis methods for calculation of internal and external, pressurized and unpressurized airplane compartment pressures during rapid discharge of cabin pressure. References to the applicable current FAA and EASA rules and advisory material are provided. While rules and interpretations can be expected to evolve, numerous airplanes have been approved under current and past rules that will have a continuing need for analysis of production and field modifications, alterations and repairs. The data and basic principles provided by this report are adaptable to any compartment decompression analysis requirement.

This document summarizes types of heat sinks and considerations in relation to the general requirements of aircraft heat sources, and it provides information to achieve efficient utilization and management of these heat sinks. In this document, a heat sink is defined as a body or substance used for removal of the heat generated by thermodynamic processes. This document provides general data about airborne heat sources, heat sinks, and modes of heat transfer. The document also discusses approaches to control the use of heat sinks and techniques for analysis and verification of heat sink management. The heat sinks are for aircraft operating at subsonic and supersonic speeds.

The purpose of this SAE Aerospace Recommended Practice (ARP) is to establish recommendations for the design, installation and testing of air vehicle vapor cycle refrigeration systems. These recommendations are representative of the refrigerant cycles.

This document considers the cooling of equipment installed in equipment centers, which usually consist of rack-mounted equipment and panel mounted equipment in the flight deck. Instances where these two locations result in different requirements are identified. This document generally refers to the cooled equipment as E/E equipment, denoting that both electrical and electronic equipment is considered, or as an E/E equipment line-replaceable-unit (LRU). The majority of cooled equipment takes the form of LRUs. The primary focus of this document is E/E equipment which uses forced air cooling to keep the equipment within acceptable environmental limits. These limits ensure the equipment operates reliably and within acceptable tolerances. Cooling may be supplied internally or externally to the E/E equipment case. Some E/E equipment is cooled solely by natural convection, conduction, and radiation to the surrounding environment.