Browse Topic: Heating, ventilation, and air conditioning systems (HVAC)
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) 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 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
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
Energy efficiency in both internal combustion engine (ICE) and electric vehicles (EV) is a strategic advantage of automotive companies. It provides a better user experience that emanates amongst others from the reduction in operation expenses, particularly critical for fleets, and the increase in range. This is especially important in EVs where customers may experience range anxiety. The energetical impact of using the air conditioning system in vehicles is not negligible with power consumptions in the range of kilowatts, even with a stopped vehicle. This becomes particularly important in areas with high temperature and humidity levels where the usage of the air conditioning systems becomes safety factor. In such areas, drivers are effectively forced to use the air conditioning system continuously. Hence, the air conditioning system becomes an ideal choice to deploy control strategies for optimized energy usage. In this paper, we propose and implement a control strategy that allows a
In automotive air conditioning systems, compressor is used to convert low pressure low temperature refrigerant into high pressure high temperature refrigerant. Various types of compressors like swash plate, rotary vane, scroll etc. are widely used in the automotive industry for air conditioning applications. In rotary vane compressors, thermal protector is used as a safety device, designed to prevent the compressor from overheating during refrigerant compression process. When the discharge temperature exceeds the preset limit of thermal protector, the thermal protector will activate and stop the electrical supply to compressor clutch to stop the compressor operation thereby preventing potential damage to air conditioning system, engine, and other nearby parts of the vehicle. This technical paper explores the various real-world scenarios for a hot country like India, which may result into higher discharge temperatures of compressor resulting into activation of thermal protector. The
Electric Vehicles and Battery-Fuel_Cell hybrid vehicles are increasingly becoming popular in the market, especially in the commercial vehicle segment. Range estimation and control is of paramount importance as it is the main cause of anxiety among the vehicle owners. This paper discusses application of Reinforcement Learning (RL) to achieve range control. In RL, the learning agent choses actions dependent on the state of the environment and gets a reward in return. Ultimately the agent will learn the policy of choosing the actions for each state such that his long-term reward is maximized. The technique of RL has been applied for various scenarios where in a look up table (between the states of a system and actions to be taken) needs to be developed for optimal performance. In this paper, we use RL to manipulate other energy sources and sinks like Fuel Cell and HVAC (in addition to the battery which is the main energy source) for range control, and thereby achieve the optimal
Vehicle HVAC noise performance is an important vehicle design validation criterion since it significantly links the brand image of a vehicle. It affects the customer’s buying decision and the business of selling vehicles because it directly affects driving comfort. Customers expect continuous improvement in HVAC noise without compromising cooling performance. The process of cascading vehicle-level acoustic performance to subsystem and component levels becomes an important factor in the vehicle NVH development process. It was found that the component-level [HVAC unit without duct] performance of an HVAC system measured in an anechoic chamber was at par when compared to targets, whereas the subsystem-level performance [HVAC unit with duct and dashboard] was on the higher side of the targets. Advanced NVH tools were used to identify the source of noise at the subsystem level. It helped to locate the source and its transfer path. A design modification done at the transfer path location
The purpose of air conditioning (AC) duct packing is multifaceted, serving to prevent condensation, eliminate rattle noise, and provide thermal insulation. A critical aspect of duct packing is its adhesive quality, which is essential for maintaining the longevity and effectiveness of the packing's functions. Indeed, the challenge of achieving adequate adhesivity on AC ducting parts is significant due to the harsh operating conditions to which these components are subjected. The high temperatures and presence of condensation within the AC system can severely compromise the adhesive's ability to maintain a strong bond. Moreover, the materials used for these parts, such as HDPE, often have low surface energy, which further hinders the formation of a durable adhesive bond. The failure of the adhesive under these conditions can lead to delamination of the duct packing, which can result in customer inconvenience due to rattling noises, potential electrical failures if condensed water
Tank Technologies, a company producing porcelain-lined water heaters, faced significant challenges with their manual cutting processes. Challenges in the cutting process are detrimental in an industrial landscape where speed requirements and cost pressures are high. The introduction of Hirebotics’ Cobot Cutter significantly improved their operations, drastically reducing rework, improving cycle times, and elevating overall efficiency
During design development phases, automotive components undergo a strict validation process aiming to demonstrate requested levels of performance and durability. In some cases, specific developments encounter a major blocking point : decoupling systems responsible for optimal acoustic comfort performances. On the one hand, damping rubbers need to be soft to comply with noise, vibration & harshness criteria. However, softness would provoke such high amplitudes during vibration endurance tests that components would suffer from failures. On the other hand, stiffer rubbers, designed for durability purposes, would fail to meet noise compliance. The rubber design development goes through a double-faced dilemma : design with acceptable trade-off between NVH and durability, and efficient ways to develop compliant designs. This paper illustrates two case studies where different methodologies are applied to validate decoupling systems from both acoustic and reliability perspectives. The goal was
One of the key problems of battery electric vehicles is the risk of severe range reduction in winter conditions. Technologies such as heat pump systems can help to mitigate such effects, but finding adequate heat sources for the heat pump sometimes can be a problem, too. In cold ambient conditions below −10°C and for a cold-soaked vehicle this can become a limiting factor. Storing waste heat or excess cold when it is generated and releasing it to the vehicle thermal management system later can reduce peak thermal requirements to more manageable average levels. In related architectures it is not always necessary to replace existing electric heaters or conventional air-conditioning systems. Sometimes it is more efficient to keep them and support them, instead. Accordingly, we show, how latent heat storage can be used to increase the efficiency of existing, well-established heating and cooling technologies without replacing them. We investigate different possibilities for the integration
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