Modular indoor micro-climate: investigation on solid-state heating and cooling for a sustainable personalization of the thermal environment

Abstract

The ability to control the thermal environment has allowed humans to inhabit a wide range of climates, including the most extreme ones. Nevertheless, over the past century, the exponential proliferation of air-conditioning systems has severely undermined the ability to meet future energy demands, exacerbated carbon and ozone-depleting gas emissions, and impaired indoor environmental quality. The fundamental assumption of conventional air-conditioning systems stands on an idealized, thermally-homogenous zone where in which discordant differences among user preferences often remain unresolved and energy-intensive systems are required to meet room-scale heating and cooling loads. Therefore, the fruition of a more sustainable, personalized thermal environment impinges on the ability to create indoor micro-climates by contracting heating and cooling boundaries from room- to user-scale. This thesis reports on a modular, solid-state system for localized heating and cooling ‘when and where needed’ based on thermoelectric energy conversion technology coupled with a temperature-optimized thermal storage. A key result shows a factorial enhancement of the coefficient of performance relative to previous investigations, achieved by the confinement of the temperature differentials across the thermoelectric devices. The applicability of the proposed modular unit is vast: in this thesis, distributed embodiments are examined through for their technical performance and impacts on user experience. A tool for calculating radiation heat transfer rate and visualize heat flux is reported based on double area summation, with the goal to enable early-stage design optimization of radiant systems. Finally, the physio-cognitive response of individualson human subjects and technical performance of the proposed modular system, following a portable device embodiment, were examined in a controlled environment. The key results are a system coefficient of performance of 1.5 under 40W of cooling, the ability to sustain 8hrs and 3hrs of stand-alone operation for heating and cooling, and perceived shift in thermal sensation, more pronounced under cooling mode. Capacity to provide localized, energy-affordable, on-demand heating and cooling, as demonstrated in this thesis, is significant for enabling direct utilization of energy coming from renewable resources along with the ability to tailor heating and cooling delivery with diversified physio-cognitive demands.