Feasibility of condensate water recycle of split air handling unit in Chinese University buildings

Deng, Xiang; Shen, Yiyun; Yang, Senwang; Feng, Jingyang; Wang, Si; Li, Dongyue; Li, Yanru

doi:10.1016/j.enbenv.2022.10.006

Cited by 5 publications

(4 citation statements)

References 17 publications

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“…This topographical challenge leads to additional energy consumption and costs associated with lifting the reclaimed condensed water to these high locations. Moreover, the fluctuating quantity of condensed water due to humidity levels does not appeal to cooling tower operators [50][51][52]. Additionally, the term "grey water" has deterred direct application of condensed water [53,54].…”

Section: Discussionmentioning

confidence: 99%

Carbon Footprint Reduction by Reclaiming Condensed Water

Leung,

Cheng

2024

Sustainability

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Everyday activity incurs carbon footprints, which are classified as personal, production, organizational and national, and may be assessed by input–output analysis (IOA), life-cycle assessment (LCA), or the combination of LCA and IOA methods. Notwithstanding international standards, like ISO 14064 and Publicly Available Specification (PAS) released for standardization, carbon footprint results can vary and sometimes lack consistency that due to variations in data sources, crossover boundary definitions, and operational boundaries for indirect emissions. The novelty of this study is the direct utilization of condensed water in an existing cooling water system, without the need for prior wastewater treatment, as typically required for greywater. The lack of practical case studies exploring the water–energy nexus in the context of reclaiming condensed water for evaporative cooling tower systems makes this research particularly significant. This highlights that condensed water can be a straightforward and cost-effective solution for both water conservation and energy savings. This case study highlights the benefits of reclaiming condensed water as supplementary cooling water, which proved effective in water quality treatment and dilution augmentation, considering that a higher cycle of concentration (CoC) was achieved, leading to reduced bleed-off that resulted in a water saving of 44% for make-up and 80% for bleed-off water, and energy savings from 6.9% to 13.1% per degree Celsius of condensing refrigerant temperature (CRT). The analytical assessment revealed that reclaiming condensed water is a promising answer for green building and is a by-product of condensation without extra power demands, avoiding the generation of an increased carbon footprint and exacerbation of greenhouse gas (GHG) emissions from freshwater resource extraction, and for the production of energy-efficient devices or substitutions. By eliminating the need for wastewater treatment, this research enhances the practicality and feasibility of direct use of condensed water in various applications. This approach not only promotes sustainability by conserving water and energy but also renews interest among proponents of green building practices. It has the potential to accelerate the adoption of this method and integrate it into green building designs.

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Section: Discussionmentioning

confidence: 99%

Carbon Footprint Reduction by Reclaiming Condensed Water

Leung,

Cheng

2024

Sustainability

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“…Reuse of Condensate water from air conditioners in buildings. Installation of pipes used to collect all condensate water collected in ground water tanks and reused for garden flushing, flushing, and for other purposes [6].…”

Section: The Water Conservation Model Carried Out In the Previous Studymentioning

confidence: 99%

“…The water conservation model in buildings has been widely applied to other buildings around the world, but the conservation models differ from one another depending on their respective geographic conditions. Some water conservation models place more emphasis on one model alone or a combination of several other water conservation models, such as rainwater harvesting [3], watersaving plumbing fixtures [4], reuse of recycled water from gray water [5], and reuse of condensate water from air conditioners in buildings [6], and some still apply a simple model by changing the behavior of water use [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Water Conservation Model in Hotel and Apartment Building in Semarang City, Indonesia

Syahputra

2023

GEOMATE

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Environmental problems such as land subsidence, seawater intrusion, and groundwater contamination are the impacts of groundwater exploitation in hotel and apartment buildings in the city of Semarang. This research was conducted on ten buildings using a four-model approach to water conservation, which includes rainwater harvesting, water-saving plumbing fixtures, the reuse of recycled water from gray water, and condensate water from air conditioners in buildings. The results showed that rainwater harvesting contributes 13.12-166.77% of the total building water demand, depending on the size of the catchment area of the building. Rainwater harvesting can be combined with infiltration wells, but the research location is relatively shallow; the groundwater depth is less than 1 meter, so infiltration wells cannot be applied. The use of water-saving plumbing fixtures accounts for 6.4% of the total building water demand. Likewise, with gray water, the reuse of recycled water from gray water contributes 59.87-69.71% of the total building water demand. Gray water is treated at STP, then flows to RWT, then flows to WTP to be treated. Gray water should not be mixed with black water so that the treatment load at the STP and WTP is not too large. Finally, condensate water from air conditioners in buildings is no less important to note; although it contributes only 1.43% of the total building water demand, it plays a role in creating green buildings.

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“…However, the performance of the SAC drops significantly under the operation condition of high outdoor ambient temperature, and the indoor air quality cannot be guaranteed [10]. Moreover, the condensate water from the SAC is usually discharged on the spot, although the daily production of the condensate water reaches 52.99 kg during the main air-conditioning season for an SAC, resulting in the waste of the cold energy stored in the condensate water [11]. For the CACS, it is commonly serviced for large-scale public buildings [12].…”

Section: Introductionmentioning

confidence: 99%

The Review of the Application of the Heat Pipe on Enhancing Performance of the Air-Conditioning System in Buildings

Yuan,

Liu,

Zhang

et al. 2023

Processes

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An air-conditioning system (ACS), which consumes large amounts of high-grade energy, is essential for maintaining the indoor thermal environment of modern buildings. However, an ACS consumes almost half of the total energy of the building. Therefore, it is necessary to reduce the energy consumption of the ACS to promote energy conservation and emission reduction in the building sector. In fact, there is an abundance of waste heat and low-grade energies with the potential to be utilized in ACS in nature, but many of them are not utilized efficiently or cannot be utilized at all due to the low efficiency of thermal energy conversion. Known as a passive thermal transfer device, the application of a heat pipe (HP) in the ACS has shown explosive growth in recent years. HPs have been demonstrated to be an effective method for reducing building cooling and heating demands and energy consumption in ACS with experimental and simulation methods. This paper summarizes the different HP types applied in the ACS and provides brief insight into the performance enhancement of the ACS integrated with HP. Four types of HPs, namely tubular HP (THP), loop HP (LHP), pulsating HP (PHP) and flat HP (FHP), are presented. Their working principles and scope of applications are reviewed. Then, HPs used in natural cooling system, split air conditioner (SAC), centralized ACS (CACS) and cooling terminal devices are comprehensively reviewed. Finally, the heat transfer characteristics and energy savings of the above systems are critically analyzed. The results show that the performance of the HP is greatly affected by its own structure, working fluid and external environmental conditions. The energy saving of ACS coupled with HP is 3–40.9%. The payback period of this system ranges from 1.9–10 years. It demonstrates that the HP plays a significant role in reducing ACS energy consumption and improving indoor thermal comfort.

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Feasibility of condensate water recycle of split air handling unit in Chinese University buildings

Cited by 5 publications

References 17 publications

Carbon Footprint Reduction by Reclaiming Condensed Water

Carbon Footprint Reduction by Reclaiming Condensed Water

Water Conservation Model in Hotel and Apartment Building in Semarang City, Indonesia

The Review of the Application of the Heat Pipe on Enhancing Performance of the Air-Conditioning System in Buildings

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