An natural materials for the following era of HVAC applied sciences

by akoloy

An organic material for the next generation of HVAC technologies
Dehumidifiers with enhanced polyimide membranes (white disc) will probably be vitality environment friendly with a smaller carbon footprint. Credit: Dharmesh Patel/Texas A&M Engineering

On sultry summer time afternoons, heating, air flow and air-con (HVAC) techniques present much-needed reduction from the cruel warmth and humidity. These techniques, which regularly include dehumidifiers, are at present not vitality environment friendly, guzzling round 76% of the electrical energy in industrial and residential buildings.

In a brand new examine, Texas A&M University researchers have described an organic material, known as polyimides, that makes use of much less vitality to dry air. Furthermore, the researchers mentioned polyimide-based dehumidifiers can convey down the value of HVAC techniques, which at present value 1000’s of {dollars}.

“In this study, we took an existing and rather robust polymer and then improved its dehumidification efficiency,” mentioned Hae-Kwon Jeong, McFerrin Professor within the Artie McFerrin Department of Chemical Engineering. “These polymer-based membranes, we think, will help develop the next generation of HVAC and dehumidifier technologies that are not just more efficient than current systems but also have a smaller carbon footprint.”

The outcomes of the examine are described within the Journal of Membrane Science.

Dehumidifiers take away moisture from the air to a cushty stage of dryness, thereby enhancing air high quality and eliminating mud mites, amongst different helpful capabilities. The mostly out there dehumidifiers use refrigerants. These chemical compounds dehumidify by cooling the air and decreasing its potential to hold water. However, regardless of their reputation, refrigerants are a supply of greenhouse gases, a significant perpetrator for world warming.

As an alternate materials for dehumidification, naturally occurring supplies generally known as zeolites have been broadly thought of for his or her drying motion. Unlike refrigerants, zeolites are desiccants that may soak up moisture inside their water-attractive or hydrophilic pores. Although these inorganic supplies are inexperienced and have wonderful dehumidification properties, zeolite-based dehumidifiers pose challenges of their very own.

“Scaling up is a big problem with zeolite membranes,” Jeong mentioned. “First, zeolites are expensive to synthesize. Another issue comes from the mechanical properties of zeolites. They are weak and need really good supporting structures, which are quite expensive, driving up the overall cost.”

Jeong and his crew turned to an economical natural materials known as polyimides which can be well-known for his or her excessive rigidity and tolerance for warmth and chemical compounds. At the molecular level, the fundamental unit of those high-performance polymers are repeating, ring-shaped imide teams related collectively in lengthy chains. Jeong mentioned the enticing forces between the imides provides the polymer its attribute power and thus a bonus over mechanically weak zeolites. But the dehumidification properties of the polyimide materials wanted enhancement.

The researchers first created a movie by rigorously making use of polyimide molecules on just a few nanometers-wide alumina platforms. Next, they put this movie in a extremely concentrated sodium hydroxide resolution, triggering a chemical course of known as hydrolysis. The response brought about the imide molecular teams to interrupt and change into hydrophilic. When seen beneath a high-powered microscope, the researchers uncovered that the hydrolysis reactions result in the formation of water-attractive percolation channels or highways throughout the polyimide materials.

When Jeong’s crew examined their enhanced materials for dehumidification, they discovered that their polyimide membrane was very permeable to water molecules. In different phrases, the membrane was able to extracting extra moisture from the air by trapping them within the percolation channels. The researchers famous that these membranes may very well be operated constantly with out the necessity for regeneration because the trapped water molecules go away from the opposite facet by a vacuum pump that’s put in inside a normal dehumidifier.

Jeong mentioned his crew rigorously designed their experiments to partial hydrolysis whereby a managed variety of imide teams change into hydrophilic.

“The strength of polyimides comes from their intermolecular forces between their chains,” Jeong mentioned. “If too many imides are hydrolyzed, then we are left with weak material. On the other hand, if the hydrolysis is too low, the material won’t be effective at dehumidification.”

Although polyimide membranes have proven nice promise of their potential use in dehumidification, Jeong mentioned their efficiency nonetheless lags behind zeolite membranes.

“This is a new approach to improve the property of a polymer for dehumidification and a lot more optimizations need to be done in order to further enhance the performance of this membrane,” Jeong mentioned. “But another key factor for engineering applications is it has to be cheap, especially if you want the technology to be reasonably affordable for homeowners. We are not there yet but are certainly taking strides in that direction.”

Polyimide membranes for the purification of natural gas

More info:
Sunghwan Park et al, Enhancing air-dehumidification efficiency of polyimide membranes by producing hydrophilic Poly(amic acid) domains utilizing partial hydrolysis, Journal of Membrane Science (2020). DOI: 10.1016/j.memsci.2020.119006

An natural materials for the following era of HVAC applied sciences (2021, March 30)
retrieved 31 March 2021

This doc is topic to copyright. Apart from any honest dealing for the aim of personal examine or analysis, no
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