SITIS Archives - Topic Details
Program:  SBIR
Topic Num:  N102-114 (Navy)
Title:  Innovative Thermoelectric Cooling Augmentation for E-2D Liquid Cooling System
Research & Technical Areas:  Air Platform, Materials/Processes

Acquisition Program:  PMA-231 - E-2D Advanced Hawkeye – ACAT I
 RESTRICTION ON PERFORMANCE BY FOREIGN NATIONALS: This topic is “ITAR Restricted”. The information and materials provided pursuant to or resulting from this topic are restricted under the International Traffic in Arms Regulations (ITAR), 22 CFR Parts 120-130, which control the export of defense-related material and services, including the export of sensitive technical data. Foreign nationals may perform work under an award resulting from this topic only if they hold the “Permanent Resident Card”, or are designated as “Protected Individuals” as defined by 8 U.S.C. 1324b(a)(3). If a proposal for this topic contains participation by a foreign national who is not in one of the above two categories, the proposal may be rejected.
  Objective:  Develop innovative approaches utilizing thermoelectric cooling to augment the E-2D Liquid Cooling System (LCS).
  Description:  The E-2D utilizes a Polyalphaolefin (PAO) based LCS as the primary method for cooling certain equipment. The system operates at a 50 gallons per minute (gpm) flow rate capacity with an inlet temperature requirement of 120 degrees Fahrenheit for ground operations and 106 degrees Fahrenheit for in flight operations. The system meets all the system requirements but there is always the possibility of system growth over time. Due to numerous air vehicle constraints, thermoelectric cooling is a good option for system augmentation. Innovative concepts are sought to augment the E-2D liquid cooling system using thermoelectric cooling to create an additional 10-20 Fahrenheit degree temperature drop in the system upstream from the inlet. Thermoelectric cooling utilizes the well known Peltier Effect which relies on the principle of applying a voltage to a thermocouple made of dissimilar metals to induce a temperature difference across the junction. This technology is used in commercial applications as well as military applications, i.e. submarines. Conventional methods of increasing Environmental Control System (ECS) capacity would require significant system redesign. Incorporation of thermoelectric cooling can be accomplished with minimal modifications utilizing available aircraft electrical power.

  PHASE I: Develop initial concept design for an efficient thermoelectric cooling system to augment a liquid cooling system. Demonstrate technical feasibility of the system's ability to decrease the temperature of PAO.
  PHASE II: Provide practical development of a production-scalable system and implement the recommended system developed under Phase I. Evaluate and demonstrate the systems ability to augment the LCS through laboratory testing and it's ability to decrease the temperature of PAO.

  PHASE III: Transition the approach to E2-D and additional platforms that could benefit from cooling augmentation. PRIVATE SECTOR COMMERCIAL POTENTIAL/

  DUAL-USE APPLICATIONS: Any commercial air vehicles with available electric power that use a liquid cooling system and needs additional cooling capabilities could possibly benefit.

  References:   1. The Heatsink Guide: Peltier Guide. (2005). In "the Heatsink Guide. Retrieved from http://www.heatsink-guide.com/peltier.htm 2. E2-D Advanced Hawkeye. (2009). In Northrop Grumman Product Website. Retrieved from http://www.as.northropgrumman.com/products/e2dhawkeye/index.html 3. Peltier Information. (2009). In Peltier Device Information Directory. Retrieved from http://www.peltier-info.com/

Keywords:  Thermoelectric cooling; Polyalphaolefin (PAO); Liquid Cooling System; Heat transfer; Peltier Effect; Advanced Hawkeye

Questions and Answers:
Q: 1. What is the typical temperature difference at the inlet and outlet?
2. What is the inlet pipe size and inlet pressure? Thanks.
A: 1. For proposal purposes, the inlet temperature is 120 degrees Fahrenheit for ground operations and 106 degrees Fahrenheit for flight operations. The goal of this topic is to reduce this inlet temperature an additional 10-20 degrees Fahrenheit. The typical temperature difference at the inlet and outlet of the system is not needed for this proposal response.

2. The inlet pressure is typically 120-130 psia. The tubing diameter was not specified to prevent constraining the proposed solutions.

Q: Additional Information from TPOC for this topic:
The outside ambient conditions that correspond to the 120 degrees Fahrenheit PAO temperature is 103 degrees Fahrenheit at sea level and the outside ambient conditions that correspond to the 106 degrees Fahrenheit PAO temperature is a total temperature of 42.1 degrees Fahrenheit at an altitude of 18,000ft. The temperature in the bay where the thermoelectric cooler would be located has a maximum of 131 degrees Fahrenheit (typically less than 100 degrees Fahrenheit).

A change in the PAO fluid type is out of the scope of this SBIR topic. Bleed air is not available for use. Allowable footprint, PAO tubing diameter and electrical power limitations were not specified to prevent constraining the solutions proposed. An alternative cooling concept can be proposed as long as it still meets the ultimate goals of the project. Proposals should also include a concept for rejection of heat from the thermoelectric cooler.

Revised Proposal Criteria:
The thermoelectric cooling topic details the goal of creating "an additional 10-20 Fahrenheit degree temperature drop in the system upstream from the inlet". Proposers are requested to submit proposed concepts for a 3-5 degree Fahrenheit temperature drop instead of a 10-20 degree Fahrenheit temperature drop. This change is a result of additional preliminary analysis indicating that the power required for a 10-20 degree Fahrenheit temperature drop cannot be accommodated.
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Q: 1. Are there shock and vibration issues that should be considered in a proposed solution?
2. If so can you specify the expected shock or vibration levels?
A: The equipment should be designed to withstand aircraft vibration and shock environments. Vibration/shock design guidance and testing levels are specified below.

MIL-HDBK-5400 paragraphs 4.6.2.5.1 and 4.6.2.5.1.2 can be used as general design guidance for vibration. MIL-HDBK-5400 Paragraph 4.6.2.5.1.4 also applies if isolators are used. Vibration testing levels would be in accordance with MIL-STD-810C, Method 514.2, Procedure I, Curve D (10g) of Figure 514.2-2 except:
There would be four resonant dwells per axis. If less than four equipment resonance's are found then use the appropriate schedule below (a to d). Each dwell shall be 30 minutes. Sweep time shall be 60 minutes per axis thus totaling 180 minutes testing per axis. Sweep rate shall not be more than 1 octave/minute.
a. If three unit resonance's are obtained, the fourth dwell shall be at 147.5 Hz.
b. If two unit resonance's are obtained, the other two dwells shall be at 147.5 Hz and 295 Hz.
c. If one unit resonance's are obtained, the other three dwells shall be at 147.5 Hz, 295 Hz and 18.4 Hz.
d. If no unit resonance's are obtained, the dwells shall be at 147.5 Hz, 295 Hz, 18.4 Hz and 442.5 Hz.

MIL-HDBK-5400 paragraphs 4.6.2.6.1 and 4.6.2.6.2 can be used as guidance for shock except that shock pulses would be in accordance with the MIL-STD-810 criteria specified below. The shock test would be conducted in accordance with MIL-STD-810E, Method 516.4, Procedures I and V (Functional & Crash). The equipment should function within specified performance and sustain no structural damage when subjected to terminal peak saw-tooth pulses specified in Procedure I with amplitude and pulse duration (20g & 11msec) per Figure 516.4-4 (Flight Vehicle Equipment). Equipment, non-operating, shall also be subjected to terminal peak saw-tooth pulses specified in Procedure V with amplitude and pulse duration (40 g & 11msec) per Figure 516.4-4 (Flight Vehicle Equipment). Equipment should not depart from its mounts, however, permanent distortion is permitted.
Q: 1. What is maximum available area for the cooling system?
2. What is maximum temperature of the cooling object (or allowable outlet temperature of the PAO)?

A: 1. The allowable footprint was not specified to prevent constraining the proposed solutions.
2. Second question is not fully understood. As far allowable outlet temperature of the PAO, the goal of the project is to decrease the PAO fluid outlet temperature by 3-5 degrees Fahrenheit (ex. on ground 120 degrees Fahrenheit PAO reduced 3-5 degrees with cooler). The normal maximum temperature of the PAO entering the thermoelectric cooler is 120 degrees Fahrenheit.

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