A Review on Polymer Heat Exchangers for Hvac&r Applications

• Journal List
• Materials (Basel)
• v.13(21); 2020 Nov
• PMC7663544

Materials (Basel). 2020 Nov; thirteen(21): 4931.

Fouling of Polymeric Hollow Cobweb Heat Exchangers by Air Dust

Received 2020 Sep 23; Accepted 2020 Oct 29.

Abstract

Currently, liquid-to-gas heat exchangers in buildings, domestic appliances and the automotive industry are mainly made of copper and aluminum. Using plastic instead of metal can be very benign from an economic and ecology signal of view. Even so, it is required that a successful plastic design meets all the requirements of metallic heat exchangers. The polymeric hollow fiber estrus exchanger studied in this work is completive to common metal finned heat exchangers. Due to its unique design (the apply of thousands of sparse-walled microtubes continued in parallel), it achieves a loftier level of firmness and thermal performance, low pressure level drops and high operation pressure. This paper focuses on an important aspect of estrus exchanger operation—its fouling in conditions relevant to building and domestic application. In heating, ventilation and air workout (HVAC) and automotive and domestic appliances, outdoor and domestic dust are the principal source of fouling. In this report, a estrus exchanger made of polymeric hollow fibers was tested in conditions typical for indoor HVAC equipment, namely with the 20 °C room air flowing through the hot h2o curlicue (water inlet 50 °C) with air velocity of i.5 m/s. ASHRAE test dust was used as a foulant to model domestic dust. A polymeric oestrus exchanger with fibers with an outer diameter of 0.6 mm (1960 fibers arranged into 14 layers in total) and a heat transfer expanse of 0.89 m² was tested. It was proven that the smooth polypropylene surface of hollow fibers has a favorable antifouling characteristic. Fouling evolution on the metallic oestrus transfer surfaces of a similar surface density was most twice equally quick as on the plastic one. The experimental results on the plastic heat exchanger showed a 38% decrease in the heat transfer rate and a 91% increase in pressure drops after eighteen days of the experiment when a total of 4000 g/thousand^two of the exam dust had been injected into the air duct. The decrease in the heat transfer charge per unit of the heat exchanger was influenced mainly by bottleneck in the frontal area because the first layers were fouled significantly more than the deeper layers.

Keywords: polymeric hollow fiber, oestrus exchangers, heat transfer, fouling

one. Introduction

Polymeric hollow fiber heat exchangers (PHFHEs) are an alternative to common metal heat exchangers in depression temperature applications. The advantages are the low cost of the material, their low weight and corrosion resistance. Their rut transfer surface consists of hundreds or fifty-fifty thousands of fibers with a small outer diameter, commonly 0.4–1.2 mm, and the wall thickness is about 10% of the diameter. PHFHEs were first presented past Zarkadas in 2004 [1] as an alternative to conventional shell and tube heat exchangers.

The thermal electrical conductivity of polymer materials is much lower than that of metals, which is why the awarding of polymeric heat exchangers has limited success in comparing to metallic ones [2,3]. PHFHEs are very meaty estrus exchangers that can exist used in industry and domestic settings [4]. A general review of polymer estrus exchangers is given in [5]. Typically, polymeric heat exchangers are made of tubes with a bore of 10 mm or more. These tubes have a wall thickness of i–2 mm and, due to the low thermal electrical conductivity of polymers, the resulting thermal operation of these estrus exchangers is poor. Tiny hollow fibers with a wall thickness of about 0.i mm overcome the disadvantage of polymers' low thermal conductivity.

The polymeric heat exchangers for liquid-to-gas used in this study were introduced in 2014 [6]. 2 types of oestrus exchangers made of polypropylene hollow fibers (with a wall thickness of 0.05 mm and outside diameters of 0.55 mm and 0.seven mm) with a heat transfer area of 0.two–0.25 1000^two were studied. The heat transfer functioning was studied with hot (40–90 °C) ethyleneglycol-water brine flowing within the fibers and cooling air flowing across them. The experiments showed that hollow fiber cantankerous-menses estrus exchangers tin can achieve high overall heat transfer coefficients (300–600 Due west/m^two·K).

Another study that describes the use of PHFHE in liquid-to-gas application is given in [7,8]. A heat exchanger made of polypropylene fibers was tested in standard conditions for air-conditioning, i.eastward., air temperature of 27 °C and relative humidity of l%. Dropwise condensation and adept condensate removal was observed.

To show the competitiveness of polymeric hollow fiber oestrus exchangers in relation to metallic finned tube ones, this blazon of heat exchanger was tested as an automotive radiator [9]. The heat transfer performance and pressure level drops were studied with hot (threescore °C) ethyleneglycol-h2o brine flowing within the fibers and air (xx °C) exterior. Information technology was observed that the overall heat transfer coefficients (up to 335 W/m²·K), and pressure drops are competitive in relation to conventional aluminum finned tube radiators. All the results given to a higher place are for make clean heat exchangers and practice not provide whatever details and on the fouling issue.

Air-side fouling of heat exchangers occurs through sedimentation and a eolith of particulate matter from the processed air and as a deposit associated with corrosion. Depending on the nature of the fouling (particle deposit, corrosion and biofouling), the deposit tin can consist of dust, fibers, products of corrosion or a biological deposit.

Typically, polymeric surfaces are more than resistant to biofouling than metallic surfaces [ten]. The biofilm mass deposited on polymer surfaces is several magnitudes smaller than on stainless steel surfaces. The promising low biofilm formation on the polymers is attributed to the combination of inherent surface backdrop, roughness, surface free energy and hydrophobicity. Polymeric estrus transfer surfaces are also preferably used in desalination processes. The primary reason is their resistance to corrosion fouling. Due to their chemic stability when exposed to aggressive chemicals, the fouling properties of polymers are considered to be much better than those of steel [eleven]. The kinetics and quantity of crystallization fouling on unlike polymeric surfaces were studied with the salts of calcium sulfate and calcium carbonate and compared with those on stainless steel. The promising low scaling affinity of the polymers is attributed to the fact that their surface properties are different to stainless steel.

Particulate fouling mechanisms are described in detail in the monography [12]. Polymeric surfaces are not considered separately, but iii principal factors responsible for the adhesion of particles on dry heat transfer surfaces in air are mentioned:

• (ane)

  Van der Waals forces of allure;

• (2)

  Electrostatic forces in systems of oppositely charged surfaces;

• (3)

  The larger the contact area, the greater the total attractive strength.

All iii of these factors are favorable for polymeric surfaces in comparison to metallic ones. The publication [12] shows that the Lifshitz-van der Waals constant of copper in a vacuum is eight, whilst for magnesium oxide information technology is iii and for polystyrene near 2.

Air-side pressure level drops and the oestrus transfer of finned tube heat exchangers with different types of dusts were studied past Bell [13]. The authors found that the eolith has a very significant bear on on the pressure drop, increasing the force per unit area drop of the microchannel heat exchanger by over 200% for a dust injection of 1600 g·thousand⁻². They also showed that coils with louvered fins and pocket-size fin pitches (less than 2.0 mm) are significantly more sensitive to fouling compared to wavy plate fin heat exchangers with larger fin pitches.

All-encompassing experimental work on the long-term deterioration in the thermal performance of air conditioner evaporators was performed by Ahn [14]. The authors analyzed 30 oestrus exchangers, which had been in field operation for upwardly to 7 years and reported a 44% rising in the pressure drop due to a decrease in the amount of hydrophilicity and particle deposits. The associated reduction in the thermal operation was 10–15% for samples used for seven years.

Despite particulate fouling of membrane hollow fibers used for air filtration existence studied in details by Bulejko [xv,16], there is no published data describing particulate fouling of polymeric hollow cobweb estrus exchangers by air dust. Thus, this study was carried out to examine the expectation that there would exist high fouling resistance heat exchangers made from polymeric fibers, not tubes and fins med of aluminum.

2. Experimental Procedure

2.i. Specification of the Tested Polymeric Rut Exchanger

A heat exchanger made of fiber material was tested (see Figure one). An original arroyo was utilized to achieve a uniform distribution and separation of fibers—fibers were woven to create a carpet. Fibers with an outer/inner diameter of 0.6/0.48 mm were used, and the cloth density was 55 fibers per 100 mm. The fibers were fixed in frames and formed layers of estrus transfer fabric. The heat exchanger air cross-section was 250 mm × 250 mm. There were 140 fibers per layer and in total fourteen layers were used. The total cobweb number in the oestrus exchanger was 1960 and the outside surface area was 0.89 m^two.

Tested heat exchanger made of polypropylene cobweb fabric (left) and woven oestrus transfer surface with separated fibers (right).

The superior particulate fouling resistance of the hollow fibers was predominantly linked to their surface quality. The hollow fibers were fabricated by extrusion and their final shape was obtained by elongation of the polymeric melt backside the extrusion head. The elongation and solidification of the melt took place concurrently, and the resulting surface of the fiber was very smooth due to the action of the surface tension forces. Effigy 2 shows the typical surface quality of an extruded hollow fiber fabricated of polypropylene. The left photograph in Figure 1 shows a unmarried fiber with a bore of 0.6 mm and no macroscopic defects. The right photograph shows the details of the surface. Information technology was very smooth and, in the large zoom, there was visible roughness parallel to the fiber axis, which is typical for extruded surfaces.

The polypropylene hollow fibers, macroscopic photograph with no defects (on the (left)) and the surface quality with ×8000 magnification (right).

2.2. Specification of Examination Grit

Examination dust ASHRAE Standard 52.1 (from Pulverization Technology Inc., Arden Hills, MN 55112, USA [17]) was used for the tests. It is designed for testing filters and heating, refrigeration and air conditioning system components. Information technology has also been used in testing electronic equipment and other industrial and household components. This dust is a proficient equivalent for residential indoor dust, and it tin can also approximate outside dust for condensers installed well-nigh fouling sources.

ASHRAE Exam Dust 52.ane (see references for the datasheet [eighteen]) is a custom blend of 72% ISO 12103-1. A2 Fine Test Grit, 23% carbon black powder and v% cotton linters milled in a Wiley Mill fitted with a 4 mm screen. This blend was formulated to specifications given in ANSI/ASHRAE Standard 52.2–2012 and met also the specifications for BS EN 779:2002.

ii.3. Specification of Testing Equipment and Testing Conditions

The diagram of the experiment (Effigy 3) shows the water and air circuits. The equipment allows long-term heat transfer tests to exist performed with continuous grit injection into the air circuit. The thermal performance data were computed based on the information acquired in the water circuit. The tests were washed in conditions typical for the operation regime of indoor HVAC equipment, fan coils and air handling units. The following constant parameters were maintained: air inlet temperature twenty °C, air velocity 1.5 m·due south^−ane (air velocity dropped during tests as fouling increased and was adjusted using a shutter to regulate air flow), relative humidity twenty–30%, water inlet temperature 50 °C and water flow rate 430 L/h (this relatively loftier h2o period rate was chosen in society to achieve uniform temperature distribution on the fiber surface).

Diagram of the experimental setup.

Exam dust was injected into the organisation twice a twenty-four hours for 10 min periods. Throughout the fouling evolution the air-side pressure drib rose due to the deposits in the air filter and on the oestrus exchanger, and thus the regulating shutter should be used to maintain abiding air velocity of i.5 g/south.

A picture showing the heat exchanger connected to the entrance of the wind tunnel can be seen in Figure 4. Connection of air temperature sensors and the pressure connection to the differential manometer can likewise be seen.

Front side of the estrus exchanger connected to the entrance of the wind tunnel afterwards injection of 200 one thousand of the test grit.

The tested heat exchanger was placed in the wind tunnel and tested for 18 days. For the first half dozen days 12.v g of dust was introduced each solar day (200 chiliad per m² of frontal area). For days 7–xviii, the corporeality of dust was doubled to 25 g a day (400 yard per g² of frontal area).

3. Results and Word

Tabular array 1 includes selected data collected during the experiment. There was air inlet temperature (based on the mean value taken from two sensors); outlet air temperature (based on the hateful value taken from six PT100 sensors, Norwalk, CT, USA); air velocity (measured by an anemometer); water flow rate, which was a constant 0.43 m³/h, and inlet h2o temperature, which was a constant 50 °C, and the measured heat transfer rate and pressure drops. All temperatures were measured using PT100 (i/3 DIN Course A precision, Norwalk, CT, USA) sensors with an accuracy of ±0.i °C. H2o menstruation rate was measured with Krohne Waterflux 3300 menstruum meter with accuracy ±0.2%. Pressure level drop was measured with column manometer MM 200600 (HK Instruments, Keihästie, Finland) with accurateness ±v Pa. Air velocity was measured with OMEGA HHF-SD1 (Norwalk, CT, USA) hot wire anemometer with accurateness ±10%. Standard departure of values of rut transfer charge per unit was 5% and force per unit area drops 10%.

Tabular array ane

Review of experimental data.

Twenty-four hours	Injected Dust Mass, g	Relative Grit Mass, one thousand k−2	Air Inlet T, °C	Air Out T, °C	Air Speed, m/s	Water Outlet T, °C	Heat Transfer Rate Q, Westward	dp, Pa
one	0	0	nineteen.3	42.9	1.50	44.9	2592	43
2	13	200	19.2	42.9	1.l	44.eight	2600	43
4	25	400	19.3	42.9	1.45	44.9	2497	43
five	38	600	19.2	43.one	1.45	45.0	2528	43
6	fifty	800	nineteen.ii	43.0	1.49	45.0	2558	43
seven	75	1200	19.five	42.4	ane.57	44.8	2604	43
8	100	1600	19.4	42.5	i.49	45.0	2488	45
9	125	2000	19.three	42.7	1.46	45.1	2468	47
x	150	2400	19.iii	43.1	1.xxx	45.3	2276	51
12	175	2800	eighteen.vii	43.4	1.31	45.v	2214	57
13	200	3200	21.5	43.5	1.35	45.six	2332	64
sixteen	225	3600	20.five	44.one	1.27	46.0	2108	73
xviii	250	4000	xix.v	45.4	1.07	46.vii	1629	83

In the following section, some important points of the experiment are described and photographically documented. Subsequently 4 days of an experiment and the injection of 400 g g⁻² of test dust, there are simply a small number of separated particles on the fibers (see Figure five). At that place was a pocket-size reduction in the heat transfer charge per unit (iv%) and the pressure drop was not affected. It tin be seen that the deposit was non completely uniformly distributed across the oestrus exchanger frontal area, with the middle (zone ane) more fouled and the balance (zone ii) less. This can exist explained by the position of the dust injection window, which is in the middle of the tunnel. Even the 1 m long gap between the injection window and the heat exchanger was not enough to uniformly mix the dust into the airflow.

Heat exchanger surface after injection of 400 g thou⁻ⁱⁱ of test dust (left). There is seen that the fouling is not compatible beyond the rut exchanger cross-department. Fibers of zone 1 (come across magnification on the (right)) are more than fouled with lot of deposit on the frontal part of the fibers, while the surface of the fibers in zone 2 has only separated particles.

Later the injection of 1200 g chiliad⁻ⁱⁱ of exam dust, the fibers were covered not by individual particles but by a layer of dust eolith (Figure 6). Fouling was not homogeneous and the deposit development was distributed co-ordinate to some kind of blueprint. This pattern may be related to air velocity distribution across the frontal area. There was no additional reduction in the heat transfer or increase in pressure drops comparing to lower loads of the grit.

Heat exchanger surface after injection of 1200 g one thousand⁻ⁱⁱ of examination dust (left). The majority of the front end surface of fibers is covered with the deposit layer. There are zones where the deposit blocks the gap betwixt the fibers (as in zone 4) or creates the lines of the blocked zones (as in zone five, see details (correct)).

Later on the injection of 2800 g thou⁻² of the exam dust, all the fibers were covered not only by separated particles, but past a layer of grit deposit and the fouling pattern can be seen very clearly (run across Effigy 7). It can exist seen that the fouling pattern (see zone eight) corresponded to one found before (zone 4 on Figure 6). There was also a massive dust deposit clogging the frontal expanse (zone 7). The oestrus transfer charge per unit was 15% lower and pressure drops increased past 32%.

Rut exchanger surface after injection of 2800 g m⁻ⁱⁱ of test dust (left); and magnification of the highly fouled zone 7 with consummate blockage of the surface (right)

Later 18 days of testing, the full dust injection reached 4000 g one thousand⁻² of examination grit and the estrus exchanger was massively fouled (38% decrease in heat transfer rate and 91% increase in pressure drops). The experiment was so stopped (come across Effigy 8). Half of the frontal surface area (zone 11) was clogged by the dust so air could not laissez passer through. The hollow fibers in zone 12 were covered in grit but air could still menstruum through. The injection of additional grit would have acquired zone 11 to grow, with a very fast rise in pressure drops. In real-life operation of air conditioning there was no regulation of the fan capacity, so the air menstruation rate would be significantly reduced, causing a deterioration in thermal functioning.

Heat exchanger surface after injection of 4000 one thousand m⁻² of test dust at the cease of measurement. Zone eleven consists of the fibers clogged by the dust, so air cannot period through. In zone 12, there is a large deposit of the dust on the fibers, but at that place is no complete clogging of the oestrus transfer area.

At the finish of the experiment, the frontal area of the heat exchanger was partially blocked by the foulant deposits, but the thermal performance was not so bad. It should be noted that the heat exchanger was formed by 14 layers of fibers. The figure of the back of the oestrus exchanger after the tests shows that the cobweb surface was clean and mostly free of massive deposits of grit particles (meet Figure ix). The majority of fouling appeared on the first cobweb layers and did not penetrate deeper. It confirms the conclusion that the pregnant reduction in transferred heat was mainly caused by the clogging of the heat exchanger frontal area. This conclusion was in line with the results found for field operated air conditioner evaporators [14] and for a laboratory tested dry cooler [19]. The fouled samples tested in the air current tunnel [xiv] show no decrease (in some cases even a small increase due to the more turbulent air flow) in heat output when the air flow was kept at the same level as for make clean samples. The results obtained for 15 heat exchangers testify that long-term grit particulate fouling influences the thermal performance mainly through the rise of the pressure level drop [14]. In the example of the tested dry libation [fifteen], a fifty% increase in air pressure level drops was found, and fouling had a slight impact on the thermal performance.

The back of the heat exchanger at the end of measurement. The fiber surface attaches only separated particles with no massive eolith layers.

There is pronounced initiation period on the record of the time development of pressure level drop and heat transfer rate (meet Figure ten). The first six days of the exam (injection of 800 m/1000²) provided data in which no fouling effect can be observed. Later a certain critical point (approximately 2400 chiliad/thousand² of test grit) the influence of fouling developed significantly faster.

Influence of fouling evolution on heat transfer and pressure level drops.

The fouling evolution results evaluated for the smoothen polymeric hollow fibers in this study were compared with the data published for classical metallic heat exchangers published in [fifteen]. The first metal heat exchanger was fabricated of copper circular tubes with sparse aluminum wavy fins. These heat exchangers were extensively used in HVAC equipment as air heaters/coolers, evaporators and condensers. The 2nd metal type was the heat exchanger with louvered fins. This type of fins was connected past brazing them to the apartment aluminum tubes. This blazon is widely used as automotive radiators. Figure xi shows a comparing of pressure level drops and the functioning for metal and polymeric heat exchangers. The significantly ameliorate antifouling characteristics of the polymeric heat transfer surface can exist observed. The amounts of dust that cause an increase of 50% in the pressure level drop was 550 g/grand² and 1000 g/m^two respectively for the two sizes of louvered heat exchanger. For the plate-fin heat exchanger it was 2100 g/m² and for the polypropylene one it was 3200 thou/grand².

Comparison of fouling characteristics of finned tube heat exchangers HXA. HXB and HXC and polymeric hollow cobweb heat exchanger. Data for HXA. HXB and HXC are adopted from Bell and Groll [13].

The tested oestrus exchanger was cleaned with a vacuum cleaner after the experiment. Cleaning procedure was performed to cheque if the eolith is fastened to the surface strongly or tin can exist removed with industrial vacuum cleaner—as it is practiced with field operated equipment. As it was expected, the deposit was completely removed and practically no particles remained on the surface. No bear witness of whatsoever damage or defects was establish on the surface too. Thermal performance was not retested subsequently the cleaning, because visual inspection was considered sufficient to confirm that the cleaning recovers the thermal functioning to its initial state.

iv. Conclusions

Particulate fouling evolution on plastic heat exchangers was experimentally studied and evaluated in the presented study. ASHRAE test grit 52.1 was used equally the fouling agent in the examination because this blazon of grit all-time represents the typical fouling conditions found on HVAC and motorcar radiators operating in cities. The presence of cotton linters in the dust (5%) was plant to be crucial for fouling evolution. The cotton wool linters initiate the fouling and have the highest impact on rising of pressure drops. Fouling development is non uniform with time and the corporeality of dust injected. It progresses very slowly at the beginning (showing no effect on heat transfer and pressure drops) and the initiation period lasts approximately until the injection of 800 one thousand/chiliad² of dust.

The tested heat exchanger was formed by 14 layers of hollow fibers with an outer diameter of 0.6 mm and cobweb spacing of 1.eight mm. The subtract in the estrus transfer charge per unit of the heat exchanger was mainly caused by the clogging of the frontal surface area. Information technology excluded a significant part of the rut exchanger from the oestrus transfer process because air could not flow through the clogged part. It acquired a pregnant increase in pressure drops besides. The behind layers of the estrus exchanger did not show big deposits of grit afterwards the test was completed.

The smooth polymeric surface shows significantly better antifouling characteristics than the classical metal heat transfer surfaces with a like density. In comparing to the metallic louvered heat exchangers, they experienced a 50% increment in pressure loss subsequently three times more than examination dust was injected. Comparison with the plate-fin metallic heat exchanger (fin spacing ii mm) showed a l% longer service time of the polymer heat exchanger for an identical rising in pressure drops.

While single fibers are highly protected from fouling due to the superior surface properties of the polymeric cloth, the fouling of dense arrangements of fibers can be more pronounced due to clogging in the gaps between them. Larger pitches (two mm or more) between the fibers are recommended to foreclose particulate fouling evolution in very dusty conditions.

Author Contributions

Conceptualization, I.A. and M.R.; methodology, I.A.; validation, I.A., T.K. (Tereza Kudelova) and T.K. (Tereza Kroulikova); formal assay, T.K. (Tereza Kroulikova); investigation, I.A.; writing—original draft preparation, I.A.; writing—review and editing, One thousand.R. and T.K. (Tereza Kudelova); supervision, K.R. All authors have read and agreed to the published version of the manuscript.

Funding

This work was supported by the Ministry of Educational activity, Youth and Sports of the Czech republic under OP RDE grant number CZ.02.i.01/0.0/0.0/16_019/0000753 "Research centre for low-carbon energy technologies".

Conflicts of Involvement

The authors declare no conflict of interest.

Footnotes

Publisher's Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

References

i. Zarkadas D.Chiliad., Sirkar K.Grand. Polymeric Hollow Cobweb Heat Exchangers:  An Culling for Lower Temperature Applications. Ind. Eng. Chem. Res. 2004;43:8093–8106. doi: 10.1021/ie040143k. [CrossRef] [Google Scholar]

2. Zaheed 50., Jachuck R.J.J. Review of polymer compact heat exchangers, with special emphasis on a polymer flick unit. Appl. Therm. Eng. 2004;24:2323–2358. doi: ten.1016/j.applthermaleng.2004.03.018. [CrossRef] [Google Scholar]

three. T'Joen C., Park Y., Wang Q., Sommers A., Han Ten., Jacobi A. A review on polymer heat exchangers for HVAC&R applications. Int. J. Refrig. 2009;32:763–779. doi: x.1016/j.ijrefrig.2008.xi.008. [CrossRef] [Google Scholar]

4. Zhao J., Li B., Li X., Qin Y., Li C., Wang S. Numerical simulation of novel polypropylene hollow fiber heat exchanger and analysis of its characteristics. Appl. Therm. Eng. 2013;59:134–141. doi: 10.1016/j.applthermaleng.2013.05.025. [CrossRef] [Google Scholar]

5. Chen X., Su Y., Reay D., Riffat S. Contempo enquiry developments in polymer heat exchangers—A review. Renew. Sustain. Energy Rev. 2016;60:1367–1386. doi: 10.1016/j.rser.2016.03.024. [CrossRef] [Google Scholar]

6. Astrouski I., Raudensky M. Polymeric Hollow Cobweb Heat Exchangers: Liquid-to-Gas Application. Ashrae Transactions; Atlanta, GA, USA: 2014. [Google Scholar]

vii. Brozova T., Bartuli Eastward. Influence of Condensation on the Outer Surface of Polymer Hollow Cobweb Heat Exchangers During Heat Transfer. American Society of Mechanical Engineers Digital Collection; New York, NY, U.s.a.: 2018. [Google Scholar]

8. Brozova T., Bartuli E., Raudensky M. Condensation on the outer surface of polymer hollow fiber heat exchangers and its influence to the estrus transfer; Proceedings of the 24th International Conference Engineering Mechanics 2018; Svratka, Czech republic. xiv–17 May 2018; pp. 117–120. [Google Scholar]

9. Krásný I., Astrouski I., Raudenský M. Polymeric hollow cobweb heat exchanger every bit an automotive radiator. Appl. Therm. Eng. 2016;108:798–803. doi: ten.1016/j.applthermaleng.2016.07.181. [CrossRef] [Google Scholar]

10. Pohl Due south., Madzgalla 1000., Manz W., Bart H.-J. Biofouling on polymeric rut exchanger surfaces with Due east. coli and native biofilms. Biofouling. 2015;31:699–707. doi: x.1080/08927014.2015.1094691. [PubMed] [CrossRef] [Google Scholar]

xi. Dreiser C., Krätz L.J., Bart H.-J. Kinetics and Quantity of Crystallization Fouling on Polymer Surfaces: Impact of Surface Characteristics and Process Conditions. Heat Transf. Eng. 2015;36:715–720. doi: 10.1080/01457632.2015.954954. [CrossRef] [Google Scholar]

12. Bott T.R. Fouling of Heat Exchangers. Elsevier; Amsterdam, The Netherland: 1995. [Google Scholar]

13. Bell I.H., Groll E.A. Air-side particulate fouling of microchannel estrus exchangers: Experimental comparing of air-side pressure drop and heat transfer with plate-fin heat exchanger. Appl. Therm. Eng. 2011;31:742–749. doi: x.1016/j.applthermaleng.2010.ten.019. [CrossRef] [Google Scholar]

14. Ahn Y.-C., Cho J.-M., Shin H.-S., Hwang Y.-J., Lee C.-G., Lee J.-K., Lee H.-U., Kang T.-W. An experimental report of the air-side particulate fouling in fin-and-tube heat exchangers of air conditioners. Korean J. Chem. Eng. 2003;20:873–877. doi: 10.1007/BF02697291. [CrossRef] [Google Scholar]

15. Bulejko P., Krištof O., Dohnal M., Svěrák T. Fine/ultrafine particle air filtration and aerosol loading of hollow-fiber membranes: A comparing of mathematical models for the most penetrating particle size and dimensionless permeability with experimental data. J. Membr. Sci. 2019;592:117393. doi: 10.1016/j.memsci.2019.117393. [CrossRef] [Google Scholar]

16. Bulejko P., Krištof O., Svěrák T. Experimental and modeling study on fouling of hollow-fiber membranes by fine dust aerosol particles. J. Membr. Sci. 2020;616:118562. doi: 10.1016/j.memsci.2020.118562. [CrossRef] [Google Scholar]

17. Industrial Powder Processing Services: Powder Engineering. [(accessed on 20 August 2020)]; Available online: https://www.powdertechnologyinc.com/

nineteen. Bell I.H., Groll E.A., König H. Experimental Analysis of the Effects of Particulate Fouling on Heat Exchanger Heat Transfer and Air-Side Pressure Drop for a Hybrid Dry Cooler. Heat Transf. Eng. 2011;32:264–271. doi: 10.1080/01457632.2010.495618. [CrossRef] [Google Scholar]

---

Articles from Materials are provided here courtesy of Multidisciplinary Digital Publishing Institute (MDPI)

---

carusowastive1990.blogspot.com

Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7663544/

Share this post