ECO-CBET: GOALI: Condensing water from the air for building dehumidification and decarbonization using thermo-responsive desiccants

2318720(双)。管理建筑物的湿度对于保持居住者的舒适性、减少对湿度敏感的制造(例如半导体)中的缺陷以及防止食品保鲜中的食源性病原体至关重要。现有的供暖、通风和空调(HVAC)系统依靠表面冷凝或吸湿材料作为干燥剂来去除空气中的水分。然而，这是一个能源效率低的过程，因为低温设定点对于足够的水分冷凝是必不可少的，并且需要额外的能量来克服除湿过程中显著的汽化热。目前，仅建筑物内的湿度控制每年就产生6亿吨二氧化碳。因此，高效的空气除湿是减少能源消耗和温室气体排放的绝佳机会，以促进可持续发展和脱碳运动，并应对气候变化。这个融合项目的愿景是启动和建立高效除湿系统，通过在建筑可持续发展、热运输、土木工程和化学工程方面的协作和跨学科努力，直接从空气中冷凝水。这项促进建筑除湿更高效的基础研究将直接造福于国民健康和国家制造业。此外，这项研究与针对大学生和职业生涯早期科学家的跨学科环境研究培训紧密结合在一起，这将使STEM工作人员受益。该项目利用具有温度相关吸附等温线的热响应(TR)干燥剂(得益于低于和高于低临界溶液温度(LCST)的热响应可切换亲水性)和高吸附能力来追求节能除湿。此外，TR型干燥剂的热响应性打破了传统干燥剂对水的固定亲和力，允许以液体形式释放水，并避免了传统干燥剂在再生过程中对水汽化的高能量要求。该项目将(1)开发具有可调LCST和不同除湿条件下最佳变温吸附等温线的耐用TR型干燥剂；(2)通过建模和实验验证优化设计参数，提高TR型干燥剂转轮的热质传递速率；(3)开发液态吸附水的去除技术；(4)通过硬件在环(HIL)实验来评价除湿系统中TR型转轮的效率。所提出的具有温度相关吸附等温线的除湿转轮具有较低的再生温度，并有可能绕过蒸发热。独特的特性是在再生过程中以液体的形式解吸吸附的水分，与传统的暖通空调应用方法相比，可以节省高达6倍的能源，从而节省高达30%的碳排放。此外，来自空气的冷凝水可以被收集起来，用于缓解干旱气候下建筑作业中的水资源短缺。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

2318720 (Shuang). Managing the humidity of buildings is essential for maintaining occupant comfort, reducing defects in moisture-sensitive manufacturing (e.g., semiconductors), and preventing foodborne pathogens in food preservation. Existing Heating, Ventilation, and Air-conditioning (HVAC) systems rely on either cold surface condensation or hygroscopic materials as desiccants to remove moisture from air. However, this is an energy-inefficient process due to the low-temperature setpoint essential for sufficient moisture condensation and the extra energy required to overcome significant enthalpy of vaporization in dehumidification. Currently, humidity control in buildings alone is responsible for 600 million tons of CO2 annually. Hence, efficient air dehumidification represents an excellent opportunity to reduce energy use and greenhouse gas emissions to facilitate the sustainability and decarbonization movement and counteract climate change. The vision of this convergent project is to initiate and establish high-efficiency dehumidification systems that directly condense water from the air through collaborative and interdisciplinary efforts in building sustainability, thermal transport, civil engineering, and chemical engineering. This fundamental research promoting more efficient building dehumidification will directly benefit national health and national manufacturing. Furthermore, the research is closely integrated with interdisciplinary environmental research training for college students and early-career scientists, which will benefit the STEM workforce.This project pursues energy-efficient dehumidification utilizing Thermo-Responsive (TR) desiccants with temperature-dependent adsorption isotherms—benefiting from the thermo-responsive switchable hydrophilicity below and above the Lower Critical Solution Temperature (LCST)—and high adsorption capacity. In addition, the thermo-responsiveness of TR desiccants breaks traditional desiccants’ fixed affinity to water, which allows for the release of water in liquid form and avoids the high energy requirements of water vaporization in traditional desiccants during the regeneration. The project will (1) develop durable TR desiccants with tunable LCSTs and optimum temperature-dependent adsorption isotherms for different dehumidification conditions, (2) improve the heat and mass transfer rate of TR desiccant wheels by optimizing the design parameters through modeling and experimental validation, (3) develop techniques to remove the adsorbed water in liquid form, and (4) evaluate the efficiency of the TR desiccant wheel in the dehumidification system by performing a hardware-in-the-loop (HIL) experiment. The proposed TR desiccant wheel with temperature-dependent adsorption isotherms leads to low regeneration temperatures and the potential to bypass the heat of evaporation. The unique property of desorbing the adsorbed moisture in the liquid form during the regeneration saves up to 6x energy compared to traditional approaches in HVAC application, which saves up to 30% carbon emission. Moreover, condensed water from the air can be collected and used to alleviate water scarcity in building operations in arid climates.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.