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The high electrical power demand and heat rejection characteristics of a high energy laser pose new challenges to airframe power and thermal system designers. Typically, the power demand requires additional power storage devices and electrical generator upsizing which will adversely impact the engine performance and installation envelope. The thermal system is complicated by an already limited onboard heat sink, resulting in a bulkier system. Utilizing conventional approaches, the aircraft will suffer from additional weight, less available installation volume, and lower overall performance. This paper presents a potential integrated power and thermal system with attributes to minimize aircraft penalty. The system is a collection of various integration techniques that will be discussed individually for potential standalone application.

Minimizing energy use on more electric aircraft (MEA) requires examining in detail the important decision of whether and when to use engine bleed air, ram air, electric, hydraulic, or other sources of power. Further, due to the large variance in mission segments, it is unlikely that a single energy source is the most efficient over an entire mission. Thus, hybrid combinations of sources must be considered. An important system in an advanced MEA is the adaptive power and thermal management system (APTMS), which is designed to provide main engine start, auxiliary and emergency power, and vehicle thermal management including environmental cooling. Additionally, peak and regenerative power management capabilities can be achieved with appropriate control. The APTMS is intended to be adaptive, adjusting its operation in order to serve its function in the most efficient and least costly way to the aircraft as a whole.

A balance of mission capability, agility, survivability, affordability and mission range is a key to the advanced fighter aircraft design. The advanced fighter aircraft is equipped with high power and density electronic equipment to achieve a superior level of mission capability. Electrical power supplied to this equipment is generated by engine powered generator. The heat generated by this equipment typically is cooled by an onboard environmental control system (ECS) operated by high-pressure pneumatic air from the engine compressor. Both the supplied power and power generating the cooling source are a power extraction from the engine. As fuel is the sole energy resource in the aircraft, this power presents a penalty of the use of fuel and results in reduction in the mission range. The challenge to ECS designer is to maximize the cooling capacity with the minimum energy consumption.

The escalation of vehicle operating costs due to continuously rising fuel prices has prompted aircraft designers to focus on more energy efficient designs. Among the heavy energy consumers in aircraft operations, the thermal management system is one of the largest. This is especially true of the refrigeration system powered by engine bleed air power. With the push towards more electric vehicles, an entirely new trade space has been opened up with regards to electric thermal management and the cost of bleed air versus electrical power. Despite favorable energy savings, the electric approach has increased the burden on the propulsion engine shaft power extraction systems (gearbox and drive train), electrical generators, power conditioning units, and electrical distribution systems. This paper presents potential architectures which utilize energy recovery and integration principles to address the challenges on the power generating system.

The rapid increase of liquid cooling demand from high-power and high-density avionics in military aircraft has been a challenge for aircraft cooling system designers. A number of state-of-the-art approaches were presented in SAE 2003-01-2399. This paper is a continuation of that discussion on the advancement of environmental-control-system design to meet the higher demands for liquid cooling. In this paper, another advanced environmental control system will be presented. The advanced system is one of a new generation of “bootstrap” air-cycle cooling systems. Similar to a traditional bootstrap air-cycle system, the advanced system is powered by high-pressure engine bleed air and uses ambient ram air and/or on-board fuel as a heat sink. However, unlike a typical air-cycle system, the advanced system maximizes usage of engine bleed pressure to form a recirculation flow path.