Viability of loop heat pipes for space solar power applications

Abstract

The primary thermal management issue associated with Space Solar Power (SSP) is the need to acquire, transport and reject waste heat loads, on the order of 3.8 GW, from the transmitter to remote radiator locations. Previous conceptual studies have focused on transporting these loads to large remote radiators. These concepts assumed the ability to transport the heat either passively or mechanical over large transport distances of 100 meters or more. The results of this study have provided new insight regarding the feasibility and limitations of LHPs for Space Solar Power applications. New technology development areas have been identified for both traditional LHPs and liquid metal LHPs.

Parametric analysis of loop heat pipe operation: a literature review

“…According to Baumann and Rawal [8], the liquid thermal conductivity has two significant effects on the LHP performance. Firstly, a low liquid conductivity reduces the heat transfer coefficient in the evaporator, thus limiting the heat transport capability.…”

“…NCGs can be generated for a number of reasons, listed by Ku [33] and Baumann and Rawal [8]. According to Ku [33], the presence of gas in the compensation chamber increases the temperature difference across the wick and consequently, the loop operating temperature.…”

“…The LHP was developed and tested in 1972 in the former Soviet Union [1]. The development of LHPs was a response to the challenge of the increasing needs of electronic systems, and with the specific demand of aerospace technology, which requires high operational reliability and robustness [2][3][4][5][6][7][8][9][10]. The two-phase loops offer many advantages over heat pipes [1,11] in terms of operation against gravity, maximum heat transport capability, smoothwalled flexible transport lines, and fast diode action.…”

Loop Heat Pipe Radiator Trade Study for the 300–550 K Temperature Range

“…NASA is interested in Brayton cycle converters for Nuclear electric propulsion for missions including the proposed Jupiter Icy Moon Orbital (JIMO) mission (Mason, 2003, Siamidis et al, 2004. A radiator is required to dissipate the waste heat generated during the thermal-to-electric conversion process.…”

“…Mason (2003) discusses the overall system concept. Siamidis et al (2004) describe a typical radiator design for a Brayton system. A pumped sodium-potassium (NaK) secondary loop is used to transfer waste heat from the power converters to the heat pipe radiator.…”