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度，减少对湿度敏感的制造（例如半导体）的缺陷以及防止食品保存中的食源性病原体至关重要。现有的供暖、通风和空调（HVAC）系统依靠冷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下的过程，因为低温设定值对于足够的水分凝结和克服除湿过程中显著的蒸发焓所需的额外能量是必不可少的。目前，仅建筑物的湿度控制每年就会产生6亿吨二氧化碳。因此，高效的空气除湿是减少能源使用和温室气体排放，促进可持续性和脱碳运动以及应对气候变化的绝佳机会。这个融合项目的愿景是通过建筑可持续性、热运输、土木工程和化学工程方面的合作和跨学科努力，启动和建立直接从空气中冷凝水的高效除湿系统。这项促进建筑高效除湿的基础性研究将直接造福国民健康和国家制造业。此外，该研究与面向大学生和早期职业科学家的跨学科环境研究培训紧密结合，这将使STEM劳动力受益。该项目利用具有温度依赖吸附等温线的热响应（TR）干燥剂进行节能除湿，受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容量。此外，TR干燥剂的热响应性打破了传统干燥剂对水的固定亲和力，使水以液体形式释放，避免了传统干燥剂在再生过程中对水汽化的高能量需求。该项目将(1)针对不同的除湿条件，开发具有可调LCSTs和最佳温度依赖吸附等温线的耐用TR干燥剂；(2)通过建模和实验验证，优化设计参数，提高TR干燥剂轮的传热传质率；(3)开发以液体形式去除吸附水的技术。(4)通过硬件在环（HIL）实验，评价TR干燥剂轮在除湿系统中的效率。所提出的TR干燥剂轮具有温度依赖的吸附等温线，导致再生温度低，并有可能绕过蒸发热。与HVAC应用中的传统方法相比，再生过程中以液体形式解吸吸附的水分的独特特性节省了高达6倍的能源，节省了高达30%的碳排放。此外，空气中的冷凝水可以收集起来，用于缓解干旱气候下建筑施工中的缺水问题。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.