What is the Advantage and Disadvantage of Wall Fan

25 Mar.,2024

 

What the main current studies about language bias in peer-review?

5 answers

Recent studies have focused on analyzing language bias in peer-review processes. One study conducted a thorough analysis of fairness disparities in peer review using large language models (LMs). The study collected and maintained a comprehensive database for a specific conference, studying disparities based on author gender, geography, author, and institutional prestige. Another study investigated the existence of citation bias in peer review, specifically looking at whether citing a reviewer's own work influenced their evaluation of a submission. The study found evidence of citation bias in the review process, with submissions that cited a reviewer's work having a higher chance of receiving a more positive evaluation. These studies highlight the importance of addressing biases in peer-review processes and understanding the potential impact of language models and citation practices on the evaluation of scientific work.

What are the latest improved methods for extraction bioactive compoundsfrom plans?

4 answers

The latest improved methods for extracting bioactive compounds from plants include traditional methods such as maceration, percolation, and Soxhlet extraction, as well as modern techniques like microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), pressurized liquid extraction (PLE), supercritical fluid extraction (SFE), enzyme-assisted extraction, and the use of deep eutectic solvents. These methods offer improved yields, efficiency, and selectivity in extracting bioactive compounds from plant materials. Enzymatic extraction, when combined with other green techniques such as ultrasound extraction, supercritical fluid extraction, three-phase partitioning, ionic liquid extraction, and microwave extraction, can further enhance the advantages of enzymatic extraction. The use of deep eutectic solvents as extraction solvents has shown better extraction efficiency and higher recovery values compared to conventional organic solvents, particularly for natural target analytes and protein extraction. These improved methods contribute to the discovery and utilization of bioactive compounds from plants in various applications.

Cancer and need for palliative care

4 answers

Patients with cancer have various unmet needs that can be addressed through palliative care. These needs include the need for more information about their health, financial problems, psychological issues such as depression and anxiety, and spiritual needs. Palliative care can provide assistance in these domains and improve the quality of life for patients with cancer. Families of patients with advanced cancer also have specific needs, including coping with the diagnosis, changing family routines, and dealing with the healthcare system. Identifying available resources for families can help palliative care teams provide better support. Palliative care is particularly important for patients with glioblastoma, as it can address the wide range of symptoms and burdens that they and their caregivers experience. However, palliative care is not yet integrated into standard neuro-oncological care, highlighting the need for better integration and timing of palliative care services. The utilization of palliative care among hospitalized patients with malignant melanoma is low, and factors such as insurance type, region, hospital type, and discharge status are associated with its utilization. Documentation of palliative needs for patients with metastatic upper gastrointestinal cancer is insufficient, and there is a need for a systematic approach to identify and treat these needs.

How does perceiver effect impacts needs satisfaction ?

4 answers

Perceived needs satisfaction is influenced by various factors. In the context of consumer behavior, the mediating role of need satisfaction for competence, relatedness, and autonomy in the relationship between pro-environmental preference (PEP) and consumers' perceived well-being (PWB) has been explored. For women with breast cancer, higher perceived needs satisfaction is associated with higher health-related quality of life (HRQoL), while higher perceived needs importance is conversely associated with lower HRQoL by suppressing the positive association of perceived needs satisfaction with HRQoL. In the context of sport events, service quality and community attributes impact satisfaction and behavioral intentions of participants. In the marketing of Nestle mineral water, promotion and product quality have a positive and significant effect on customer satisfaction, while perception does not significantly influence consumer satisfaction. Perceived corporate social responsibility (CSR) has direct and positive effects on service quality, satisfaction, and repurchase intention, with service quality and satisfaction mediating the effect of perceived CSR on repurchase intention.

What are the recycling technologies of marine plastics?

5 answers

There are several recycling technologies for marine plastics. One approach is to convert the plastics to fuel gases through gasification in supercritical water driven by concentrated solar energy. Another method involves pyrolysis and distillation to produce marine gas oil (MGO) compliant with ISO8217 standards. Chemical recycling can also be used to obtain raw pyrolysis oil from plastic marine litter, which can then be further processed into virgin naphtha and marine gasoil. Additionally, 3D printing can be used to fabricate marine industry products using marine plastic waste as a source material. Furthermore, the feasibility of recovery and reuse of both reinforcement and matrix from thermoplastic composites has been investigated, offering the potential for environmental and economic benefits.

American heart association’s life’s essential 8

5 answers

The American Heart Association (AHA) has developed a new cardiovascular health (CVH) metric called Life's Essential 8 (LE8). LE8 is a scoring system that evaluates various health factors and behaviors to assess overall CVH. Several studies have examined the relationship between LE8 and different health outcomes. X. Li et al. found that a higher LE8 score was associated with lower risks of coronary heart disease (CHD), stroke, and cardiovascular disease (CVD). Another study by Xue Xia et al. showed that a higher LE8 score was associated with a greater number of years lived without CVD. Jiahong Sun et al. found that achieving a higher CVH score according to LE8 was associated with a reduced risk of all-cause and CVD-specific mortality. Vivek P. Sarma et al. also found that a higher LE8 score was inversely associated with all-cause and CVD mortality among older adults. These studies suggest that LE8 is a valuable tool for assessing and promoting cardiovascular health.

What is the importance of cohesion in teamwork?

5 answers

Cohesion is important in teamwork as it contributes to shared goals, performance outcomes, and individual satisfaction. It refers to the unity, harmony, and coordination within a team. Cohesive teams exhibit temporal coordination of interactions and develop synchrony over time. Team cohesion can be measured using temporal network motifs as a proxy. It is crucial for both task cohesion, which relates to how well team members work together, and social cohesion, which pertains to how well they get along. Cohesion leads to better individual and team performance, as well as increased satisfaction and retention. In the context of human-autonomy teams, cohesion is an underexplored topic, and understanding its dynamics is essential for effective collaboration.

What is the effectiveness of using UTAUT2 and TTF in predicting technology adoption in education in developing countries?

5 answers

The effectiveness of using UTAUT2 and TTF in predicting technology adoption in education in developing countries has been explored in several studies. UTAUT2, originally developed for commercial use, has been extended and applied to educational technologies such as e-learning, learning management systems, and instructional tools. It has been found that factors such as performance expectancy, effort expectancy, social influences, facilitating conditions, and hedonic motivation significantly and positively influence students' behavioral intentions to accept blended learning in universities. Additionally, the UTAUT2 model has been found to be generally robust in predicting technology adoption, although its predictive power may vary across different cultures. The integration of TTF with UTAUT2 has been proposed as a research model to study educational technology acceptance, providing a new perspective on predicting students' behavior intentions towards and use of virtual reality systems. Overall, these studies suggest that UTAUT2 and TTF can be effective frameworks for understanding and predicting technology adoption in educational settings in developing countries.

What are the recent developments in the use of 3D printing technology for mammalian cell culture in bioprocessing?

5 answers

Recent developments in the use of 3D printing technology for mammalian cell culture in bioprocessing include the production of scaffolds, scaffold-free spheroids, gels, bioreactors, and microchips. These platforms are made from materials such as collagen, fibronectin, gelatin, laminin, vitronectin, or synthetic materials like agarose. Techniques like 3D printing, particulate leaching, and electro-spinning are used to prepare these platforms. The aim is to create a physiological environment that closely resembles the in vivo conditions of mammalian cells/tissues/organs. 3D bioprinting, which is an extended application of additive manufacturing, is being explored for tissue engineering and regenerative medicine. It allows for the precise construction of complex tissue structures by depositing cells and extracellular matrix layer by layer. These advancements in 3D printing technology have the potential to revolutionize cell culture techniques, enabling the recreation of human organs and diseases in vitro for applications in regenerative medicine, drug discovery, precision medicine, cancer research, and gene expression studies.

What is neighborhood satisfaction?

4 answers

Neighborhood satisfaction refers to the evaluation that residents make of their living environments and their level of contentment with their neighborhood. It is an important measure of the attractiveness of a city and the quality of life experienced by its residents. Studies have shown that neighborhood satisfaction is influenced by various factors such as safety, connectivity, green and recreational areas, cleanliness, proximity to amenities, and accessibility to public transport. The presence of liveable amenities, environmental features, and social aspects of the neighborhood environment have been found to positively impact neighborhood satisfaction. However, not all components of urban vitality, such as concentration and satisfaction with green and recreational areas, are positively associated with higher neighborhood satisfaction. It is also worth noting that neighborhood satisfaction can vary among different groups, with single parents and childfree individuals experiencing lower levels of neighborhood satisfaction. Overall, neighborhood satisfaction is a multidimensional concept that encompasses various aspects of the built environment, amenities, and individual characteristics.

Does preference influence young adults’ intention to participate in household e-waste recycling?

5 answers

Preference does influence young adults' intention to participate in household e-waste recycling. Factors such as attitude, subjective norms, and perceived behavioral control have a positive impact on recycling intention. Additionally, awareness, availability of facilities, and perceived behavioral control are significantly associated with consumer e-waste recycling behavior. The study also found that government policy, financial benefits, environmental concerns, attitude, subjective norms, and perceived behavioral control play a significant role in determining young consumers' behavioral intentions toward e-waste management. These findings suggest that young adults' preference for recycling is influenced by various factors, including their attitudes, social norms, and awareness of e-waste issues.

How Fan Walls or Fan Arrays Work. Fan walls are fans configured in stackable or wall mounted modules that can be designed in various arrays to form a larger fan system. They have a host of benefits over traditional fans used in the HVAC industry that we’ll cover in this article. One of those benefits is their simple modular design which replaces the single larger, heavier fans of earlier designs.

If you prefer you can watch the Video of this presentation by scrolling to the bottom or clicking on the following link “How Fan Walls or Fan Arrays Work“.

Retrofit Air Handler for New fan Wall (Remove Old Fans)

We’ll first show you how an air handler gets renovated with a new Fan Wall System. Here we show a large air handler with one large utility style fan inside. The system will be shutdown and the fan will be removed. You can see here that the fan was removed from this air handler so that a new bulkhead sheet metal wall could be installed to hold the new fan arrays. So that is what we’ll do here. 

We’ll install the bulkhead walls, including vertical and horizontal panels, which leaves us an opening in the bulkhead for the fans. Each panel will come from the factory with a sticker that identifies which air handler it applies to, and where the panel is to be installed according to the manufacturer provided assembly drawing. 

Next the fans will be installed. Here we show what the fan might look like from the side view. Each manufacturer provides similar looking fans with various modifications. Next, we put another fan, until all five are installed. 

A quick connect box is installed inside the air handler. The quick connect box connects directly to the bulkhead wall and provides quick connection points for all the cabling coming from the fans. Each fan has power and communication wiring connected to the quick connect box. This part of the installation can be done without an electrician as the connections are just plugged into receptors at each end.

A control box will be installed on the outside of the air handler. Then the electrician will run line voltage power to the control box, and then over to the quick connection box located inside the air handler.

Fan Wall Array with Quick Connect Box and High Pressure Safety Switch

There are cable ties for quickly securing all cabling tight to the wall. The location of these ties is clearly shown on the drawings.

Then we install safety devices such as smoke detectors or pressure sensors. A high pressure limit switch prevents excessive pressure from occurring in the main duct. This will be wired to the control box, and if high pressure is sensed in the duct a signal is sent to the control box to shut-off the fans This could also be any fire/life safety device such as smoke detectors. If smoke is detected, a signal is sent to the fans control box and the fans are shut-off, this prevents smoke from being blown throughout the building.

If one fan breaks down and needs to be removed, just replace it with a blank-off panel until the new fan arrives. This allows the system to remain running using the remainder of the fans. If this were a single utility or vane axial fan that burned-out, the whole system would be down until a new fan was installed. This allows for redundancy with multiple small fans compared to one large fan. 

Built-up Fan Wall or Fan Arrays

Fan walls or fan arrays can be used for built-up systems also. They can be provided in stackable cubes in various configurations. We can have a 1 x 2 array, that is one fan high by two fans wide, or a 1 x 3, or a 2 by 3 fan array. As you can see you can increase the required airflow by increasing the number of fans in the system. All you need is the space for the fans.

Fan Wall Fan Array 2 high x 3 Wide (2×3 Fan Array)

They can easily fit through doorways and up elevators, making retrofit projects easier. The smaller fan cubes are lighter and easier to handle than single larger fans. This eliminates the need for large cranes or rental equipment.

In retrofit applications, large single utility fans or vane axial fans are often cut apart to allow for easy removal down an elevator, along with any sound traps. Fan Walls run quieter and generate less vibration than the typical fan and are used without sound traps, which also reduces any pressure drop caused by a sound trap.

Fan Wall using Stackable Fan Cubes

A 3 x 3 fan array gives us 9 fans. They’re stacked on top of each other and fasten together. Here we have a 3 x 4 fan array shown above. There will need to be a wall that isolates the discharge and suction sides of the fan. This can be done by installing some form of framing on both sides of the fan array and then closing any openings with sheet metal blank-off panels. 

Now we have 15 fans running in this built-up system providing air to our building. With all these fans, if anyone was to fail, the system has built-in redundancy as there are 14 other fans still running.

3 x 5 Fan Array = 15 fans – 1 Failed = 14 Fans Still Running (Redundancy)

The fan array also provides better laminar flow as the air is spread out across the coil face area and isn’t concentrated in one area as you might get with a single utility or vane axial fan. Retrofits can be done over a weekend when the building is unoccupied, reducing or eliminating any down time for the AC system.

Control Systems for Fan Arrays

Here are a few ways in which these fans can be controlled with the use of a DDC programmable controller that uses inputs and outputs with the option of remote control using a Building Management System. Remember from our other basic controls videos that controllers have internally programmable logic, like mini-computers that house software specifically for the application of the equipment. See our other control videos on “Basic HVAC Controls” or “6 Steps for Designing HVAC DDC Controls”, 

They can be controlled by a supply duct static pressure sensor, which attempts to maintain a static pressure set point, or supply CFM control.  They can use return airflow control using building pressurization setpoints, or return air fans can be controlled as a percentage of the supply CFM. There are various other methods of control using the controller.

These controllers can be programmed to only run the system during building operational hours by the use of schedules. The controllers can track alarms, scale the CFM of individual fan cells, enable or disable fan cells. 

Air Handler with Return Air and Supply Air Fan Walls

What are some of the Benefits to using a Fan Wall Array?

Some of the benefits to using a Fanwall array is their lighter weight and ease of installation, reduced noise and vibration levels compared to other fan types, reduced building space required, the reduction in downtime due to motor failure because of the use of multiple smaller fans in lieu of a single larger fan installation. 

  • Easier Installation – Smaller Fan Modules are lighter and easier to handle than one large fan. Easier to move and rig the fan array’s smaller modules which can fit through doorways, hallways, stairways or elevators.
  • Reduced Noise & Vibration
  • Redundancy – Multiple Smaller Fans prevent full shutdown in case of motor failure in lieu of the use of one large fan motor.
  • Saves on Real Estate/Building space – Fan arrays usually require less space than a single large fan which often has a sound attenuator that can be removed.
  • Reduced static pressure with the removal of any previously installed sound attenuators. 
  • Usually less costly to install while improving operational efficiency and saving energy & money
  • Eliminates the need for crane rigs or expensive rental equipment or removing walls for equipment access.
  • Reduced cost for maintenance and service
  • Better laminar flow through the coils.
  • Retrofits can be done over a weekend when the building is unoccupied, reducing or eliminating any down time for the AC system.
  • Replaces old technology belt-driven forward curved fans or axial fans. Forward curved fans are less efficient than a backward curved fan found on fan Arrays.
  • No dust or dirt generated by the motors belts deterioration. Important for spaces requiring clean air.
  • EC permanent magnet motor
  • Direct drive motor
  • High efficiency control system
  • High efficiency plug fan
  • Smaller fans and motors running at peak efficiencies

Fan Wall arrays can be used to retrofit an existing built-up larger fan system, Air Handler or Packaged DX piece of equipment. When purchased as part of a new AHU or packaged unit all the components will be factory integrated with controllers and motors. This can be small 15 ton air handlers to ones over 2,000 tons that come fully integrated with Fan Wall Array. As part of a retrofit project, you’ll need to demo the existing fan system and install the Fan wall array modules and connect the electrical and control components in the field.

Fan Array Control Optimization

The fanwalls multiple fan array is optimized for efficiency with controls that vary the speed and quantity of fans in operation at any one time to meet the system requirements.

Each Fanwall manufacturer provides various control packages, from the simple speed controller to the more premium control packages that monitor static pressure and CFM. There may be an option for a fireman’s override, fan RPM, energy usage, individual fan alarm and integration into a BMS system via BACnet.

Variable Frequency Drives

You can add a VFD for each fan or combination of fans to provide for dedicated speed control and a means for on/off fan operation. Various Fan Wall Array manufacturers handle this differently, including one manufacture that includes pre-wired VFD’s, not need for electrician to wire individual fans as they have a simple plug to a local panel

Advantages

Depending on the choice of Fanwall manufactures there are some additional materials and labor required beyond what you purchase from the manufacturer. If your fan wall comes with VFD’s in lieu of ECM motors for speed control, then you’ll need to mount them and wire them to the motors, programming VFD’s and providing electrical to each motor. Fan wall manufactures like Q-PAC avoid most of these issues because they use ECM motors and provide fan power plugs that connect easily to their quick connect panels.

ECM vs VFD Speed Control

Some Fan walls use VFD’s for speed control either with a dedicated VFD per motor or with one VFD handling multiple fan motors.

Some field installed items when using Fanwalls

In addition to the Fans themselves, the following items if provided by the Fanwall manufacture will most likely have to be field installed; VFD’s, BDD’s, Bulkhead walls, Control Panels, Electrical Conduit & Wire, Structural Supports, duct transition (tying into exist systems)

Physical Size

A single fan array can be a 26” x 26” square module approximately 18” deep and weigh 120 pounds. There are fan wall versions that can be completely broken down to get through an existing 19” wide air handler access panel, and then rebuilt inside the unit. With only a cordless drill, wrench, caulk gun and tape measure. According to Nortek it takes approximately 30 minutes to reassemble a single fan cell, and two to three people to move the assembled cells into place.

The cells arrive at the jobsite tagged by the manufacturer as to where they’re to be installed within the air handler. Each cell is bolted to the adjacent cell, while the bottom cells are bolted to the floor. Once all the cells are installed, sheet metal blanking plates are used to cover any top and side openings left over. An electrical chase is provided along the length of the array to protect the power wiring that connects each cell to the electrical power.

Sound Attenuation

Compared to the utility fan or vane axial fan that the plenum fans often replace, the Fan Wall Array is much quieter. Any existing sound traps are removed as the fans are quieter and the cubes that house the fans are provided with acoustic insulation. With multiple smaller direct drive motors the noise levels are less than those of a single large utility style fan or vane axial fan.

Engineering and Supplier Provided Items

If this is a design/build retrofit project for a built-up system, then you’ll need to provide the jurisdictional authority with a set of MEP and Structural drawings showing the new design. This might include structurally engineered drawings showing how the fan array is supported to the structure when using a headwall assembly as opposed to a stackable fan array.

If you are using the Q-PAC fan array system to replace fans in an Air Handler, then you should receive a fully engineered and sized system that fits within the existing air handler. The Q-PAC supplier should provide the following on an Air Handler retrofit:

  • Fully Engineered and sized fan array to meet specified CFM and ESP with ECM motors
  • Factory supplied/field installed modular fan bulkhead wall assembly with precut fan inlets
  • Plug and Play wiring to allow quick connect harness to simply plug into connect panel
  • CFM and Static Pressure measurement plastic tubing
  • Optional – Blank off panels incase a motor goes down.
  • Possibly Factory Supervised Startup. 
  • 5-Year Parts and Labor Warranty. (Confirm with supplier)

Energy Efficiency

The motors used in a Fan Wall Array have individual on/off control and variable speed control, allowing them to maintain operating efficiently along the demand curve of the system. With the variety of fan sizes and quantity of fans available for a fan wall array making it easier to optimize selection to match the best performance requirements.

Fan Walls & Fan Arrays

What is the Advantage and Disadvantage of Wall Fan

How Fan Walls or Fan Arrays Work

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