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A Guide to Refrigerant R454B and R32

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September 10, 2024

Why are we changing refrigerants again? As the battle against high Global Warming Potential refrigerants rages on, air conditioning manufacturers are left feeling like they’re in a never-ending game of limbo—constantly asking, how low can you go with each new refrigerant mandate. Refrigerant R454B and R32 are becoming the new darlings of the industry for smaller commercial and residential systems.

If you prefer to watch the video of this presentation, then scroll to the bottom.

R454B has a lower Global Warming Potential than R410A. R410A is being phased out like R11, R12 and R22 were. R454B has a Global Warming Potential of 466, while R410A has a value of 2,088, which is above the new threshold of 700. The higher the value the worst the refrigerant is for the environment. R32 comes in at 675, just under the mandate.

The questions we’ll answer are, how much does R32 and R454B cost compared to other refrigerants? Will I need new tools and equipment to work with R32 and R454B? Can I use R32 or R454B as a drop-in replacement for an existing R410A, or R22 system?

Effects of Global Warming Potential on Refrigerant Cost

The cost per pound of refrigerant is influenced by its Global Warming Potential (GWP) and whether it is being phased out or has restricted production:

Refrigerants with higher GWP values are more environmentally damaging and are increasingly subject to regulatory restrictions. As regulations tighten, such as those under the Kigali Amendment to the Montreal Protocol, the demand for low-GWP refrigerants rises. This demand shift can lead to a decrease in the availability of high-GWP refrigerants, driving up their cost.

The effects of GWP on Refrigerant Cost per Pound

When a refrigerant is phased out or its production is restricted, as seen with R11, R12 and R22, the supply diminishes while existing systems still require the refrigerant for maintenance. This limited supply, combined with ongoing demand, results in a significant increase in cost per pound. R410A is currently available at a reasonable cost per pound but that will start to change as production decreases and other refrigerants with lower global warming potential values are produced and installed.

Refrigerants with high GWP values and those subject to phaseouts typically become more expensive over time due to increased regulatory pressure and reduced availability.

Daikin is currently a manufacturer of R32 and residential units that use R32. New R454B AC systems will become more available in 2025. The manufacturing or importing of R-410A residential and light commercial air conditioning products is prohibited starting January 1, 2025.

Your price per pound will vary based on how much refrigerant you buy from your supplier.

Can I convert an R410A System to Refrigerant R454B

R410A systems are not compatible with R454B due to differences in refrigerant characteristics, including pressure, temperature glide, and flammability. R410A is a class A1 refrigerant, while R454B is a class A2L refrigerant which is slightly more flammable. As a result, retrofitting R410A systems to use R454B is not advisable. New systems specifically designed for R454B will be required.

R410A operates at higher pressures than R454B, making the compressor and condenser less compatible with a lower pressure refrigerant. Additionally, the components in systems designed for R410A are not suitable for use with lower flammability AL2 refrigerants like R454B. Before charging the system with R454B, you must replace these components with ones that are designed to safely handle a slightly more flammable refrigerant.

Refrigerant Comparison Chart. Can you drop-In R454B or R32 into and Existing R410A or R22 system

R-454B is not a drop-in replacement for R-410A or R22. While R-454B shares many characteristics with R-410A, its use is restricted by codes and regulations to systems specifically designed for it.

The same is true for R32. R32 is not a drop-in replacement for R410A or R22.

Can I use my existing tools and equipment on a R32 or R454B system?

A refrigeration technician might be able to use their existing R410A or R22 manifold gauges, leak detectors, vacuum pumps, refrigerant recovery machines, and other tools directly with the new R32 or R454B refrigerant systems. You will need to confirm with the manufacturer to see if it’s approved for multiple refrigerants. This is because R32 and R454B are classified as an A2L refrigerant. These refrigerants are mildly flammable, and may require tools that are specifically rated for use with A2L refrigerants.

We have found new gauge manifolds that are rated for all four refrigerants discussed here. It’s just a matter of buying the right equipment and tools. Never use a tool or piece of equipment that is not specifically approved for the refrigerant in question. You may have older tools that weren’t built to handle the new refrigerants, in which case you’ll need to buy new ones.

To work with R32 and R454B, technicians will need to use tools and equipment that are compatible with A2L refrigerants. This includes gauge manifolds, recovery machines, and vacuum pumps that are designed to safely handle the flammability of refrigerants that are classified as A2L refrigerants. Using the correct equipment is crucial to ensure safety and compliance with regulations when working with R32 or R454B systems.

Can I use the existing Refrigerant Piping

When changing from an R22 or R410A system to an R32 or R454B system, the refrigerant piping generally does not need to be replaced. This is provided that the existing piping is in good condition and appropriately sized for the new refrigerant. R32 often requires smaller pipes than R22.

However, it’s crucial to ensure that the existing piping is thoroughly cleaned and free of any residual oil or contaminants from the previous refrigerant. R454B, like other A2L refrigerants, requires the use of specific lubricants (such as POE oil) that are compatible with the new refrigerant. The system may need to be flushed to remove any incompatible oil or residue before charging with R454B.

Additionally, the piping should be carefully inspected for leaks and pressure-tested to ensure it can handle the operating conditions of the new refrigerant. If the existing piping is in poor condition or not properly sized, replacement may be necessary.

See how the latest Refrigerants compare to the older R410A, R22, R12 and R11

VAV Laboratory Fume Hood Control

MEP Academy Instructor

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September 2, 2024

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In this article, we’ll explore one effective method for managing VAV systems in laboratory settings, focusing on the sequence of operations that ensures a safe and energy-efficient environment.

If you prefer to watch the video of this presentation, then scroll to the bottom.

A common strategy for addressing exhaust and supply requirements while minimizing energy consumption is to implement a variable air volume (VAV) lab control system. This system can be as straightforward as a single exhaust fan connected to two variable-volume fume hoods, or it can scale up to include multiple fans that activate based on laboratory demand.

No matter the size of the lab, each VAV fume hood is equipped with an exhaust airflow control valve to regulate airflow through the hood. Typically, hoods used for standard research are connected to a manifolded exhaust duct that leads to roof-mounted fans. Additionally, the laboratory space is supplied with fresh air through a duct with a modulating damper to control the air’s volumetric flow.

A VAV lab system is managed to maintain a safe environment by use of the following.

Space Pressurization

Laboratories typically operate under negative pressure to contain fumes and odors. To achieve this, the control system is configured to exhaust more air than is supplied. The amount of exhaust air required is directly related to the Air Changes required, Fume Hood airflow capacity, and or the amount of conditioned supply air needed based on heat gain driven labs.

Chemical Fume Hood Flow

The VAV fume hood is equipped with a fume hood monitor, sash position indicator, controller and an airflow control valve that adjusts the airflow based on the position of the sash. While exhaust velocities vary by application, the use of 100 feet per minute is often used. If you have a 6-foot fume hood with an open sash height of 24 inches, then the volume of air would be 6-feet times 2-feet equals 12 square feet times 100 feet per minute, equals 1,200 CFM. An 18-inch open sash would equal 900 CFM. In a lab that measures 64 feet in length by 32 feet wide with a 10-foot ceiling at least 2,048 CFM would be required to achieve the 6 air changes required for this lab. If you want to learn more on how to calculate air changes per hour see our other video.

Laboratory Fume hoods with Venturi type airflow Valves

Lab Airflow Valves

A VAV laboratory controller maintains negative pressure by dynamically adjusting the fume hood exhaust valves, general airflow exhaust valves, and supply airflow valves in response to real-time conditions.

Fume Hood Exhaust Valves

The controller modulates the fume hood exhaust valves based on the sash position. When a sash is opened, the valve opens further to increase the exhaust airflow, ensuring that fumes are effectively captured and removed.

Laboratory Airflow Valve - Phoenix Style Lab Airflow Valve — Laboratory Airflow Valve

General Airflow Exhaust Valves

These valves control the overall exhaust from the lab space, beyond just the fume hoods. The controller adjusts these valves to maintain the desired negative pressure in the lab, ensuring that air flows from adjacent areas into the lab, preventing contaminants from escaping. If the fume hoods are not being used, then the General Exhaust valve will increase its airflow to maintain a negative pressure based on the position of the supply valve.

Supply Airflow Valves

To maintain balance, the controller also modulates the supply airflow valves. As exhaust airflow increases or decreases, the supply airflow is adjusted to ensure that the lab remains at a slightly negative pressure. This ensures that the lab draws in clean air from adjacent spaces, rather than allowing potentially contaminated air to escape the lab.

By coordinating the adjustments of these three types of valves, the VAV laboratory controller effectively maintains a consistent negative pressure, ensuring a safe and controlled lab environment.

Sash Position

As the sash opens, the sash sensor detects the change and signal the fume hood controller to adjust the exhaust airflow control valve to open, ensuring the desired airflow and maintaining a safe hood velocity. When the sash closes, the valve adjusts to a specific level to sustain the required face velocity. As the sash is moved to a new position the controls will respond within seconds to reposition the exhaust airflow control valve to maintain the required face velocity. This requires that the exhaust airflow control valve be able to adjust flow (CFM) from full load to the minimum required. The valves are pressure independent and will maintain the required flow when the overall system pressure fluctuates.

Fume Hood Monitor

The fume hood monitor will indicate the current velocity. There may. be a green light indicating normal operation, and a yellow light when the velocity drops below normal. Once the velocity drops too low or there is a system failure the fume hood monitor will show a red light and produce an audible alarm to alert the room occupants of a potential unsafe condition and to close the sash.

If the user spills a toxic or hazardous substances within the hood, the user can push the purge button on the hood monitor. This will close the sash to contain the contaminants.

Duct Pressure and Bypass Air

Monitoring duct pressure between chemical fume hoods or other exhaust points ensures the system maintains the appropriate negative pressure. This is to keep the lab space negative, even when VAV hood sashes open suddenly. This pressure monitoring also prevents excessive negative pressure, which could damage the exhaust valves or ductwork.

A crucial aspect of controlling duct pressure is adjusting the capacity of the exhaust fan(s) that draw air from the system. While there are various methods to regulate fan capacity, including variable frequency drives. The most common approach is to use a bypass air plenum with a modulating damper.

The bypass air plenum is located either beneath an inline fan or next to a scroll-style centrifugal fume exhaust fan. It includes a modulating isolation damper that disconnects the fan from the duct system when not in use. When sashes are closed and duct negative pressure increases, the bypass damper allows outside air to flow into the fan. This reduces the amount of air pulled from the exhaust system when hood demand is low. The benefits of this setup include:

Laboratory Exhaust Fan with Bypass Damper control

Lab Exhaust Fan

Stable operation of the exhaust fan, ensuring consistent nozzle velocity and plume rise. Exhaust fan stack velocity is crucial in laboratory fume hood exhaust systems because it ensures that hazardous fumes and contaminants are effectively dispersed into the atmosphere, away from building occupants and nearby areas. A sufficient stack velocity creates a high-velocity plume that carries pollutants to a safe height.This minimizes the risk of re-entrainment into the building’s air supply and reducing the exposure of nearby personnel to harmful chemicals. This helps maintain a safe and compliant laboratory environment.

Quick response to changes in duct pressure.

Energy savings, as reduced exhaust from the lab lowers the demand for tempered supply air

The opposite occurs when the sashes begin to open. As the VAV hood valve opens, the duct pressure becomes less negative, and the bypass dampers begin to close. This adjustment draws more air from the lab exhaust system, while the make-up air increases to maintain proper system pressure.

Summary

Lab exhaust systems are essential for ensuring a safe environment in and around laboratory facilities. However, managing chemical fume exhaust, creating high-velocity plumes, and handling 100% outside air can result in significant energy consumption. By implementing a VAV lab system and providing proper training for lab users to close their sashes when not in use, it is possible to maintain a safe environment while also reducing overall energy usage.

VAV Laboratory Fume Hood Control

Construction Estimator

MEP Academy Instructor

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August 29, 2024

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Welcome to our article on the exciting field of construction estimating! If you’ve ever wondered what goes into determining the cost and planning of construction projects, you’re in the right place. In this article, we’ll dive into the essentials of becoming a construction estimator, including the educational background you’ll need to get started, the salary you can expect, and the current job market outlook. Whether you’re considering a career change or just curious about the role, stay tuned to learn everything you need to know about this vital profession in the construction industry.

If you prefer to watch the video of this presentation, then scroll to the bottom.

A construction estimator plays a crucial role in the planning and budgeting stages of construction projects. The first thing most candidates want to know is how much does a Construction Cots Estimator make?

Expected Pay

As of May 2023, non-residential construction cost estimators in the United States earn a competitive salary, with the U.S. Bureau of Labor Statistics reporting an annual mean wage of $94,430. This figure reflects the critical role these professionals play in accurately forecasting the costs of large-scale construction projects, ensuring that budgets are realistic and that projects are completed efficiently. With experience and expertise, many estimators can expect to earn well above this average, particularly in regions with high demand for construction services. What does an estimator do every day?

Construction Estimator Job Duties

Review project plans, specifications, and drawings to understand the scope of work and project requirements.
Calculate the costs of materials, labor, equipment, and other expenses involved in the project. This often involves creating detailed cost estimates and budgets.
Prepare and submit detailed bids or proposals to potential clients or contractors. This includes gathering quotes from subcontractors and suppliers.
Measure and quantify materials, labor, and equipment needed for the project from blueprints or design documents.
Identify potential risks and challenges that could affect the cost or timeline of the project. Propose solutions or contingencies to address these risks.
Monitor and manage costs throughout the project lifecycle to ensure that the project remains within budget. This includes analyzing and adjusting estimates as needed.
Work closely with project managers, architects, engineers, and other stakeholders to ensure that estimates are accurate and reflect project requirements.
Stay updated on current market rates for materials, labor, and equipment to ensure that estimates are competitive and realistic.
Maintain detailed records of estimates, bids, and project changes. Prepare reports and documentation for review and approval.
Review and analyze contracts and agreements to ensure that they align with the estimates and scope of work.

Estimators need strong analytical skills, attention to detail, and a thorough understanding of construction methods and materials to perform their job effectively. What type of education is required?

Education

For those looking to break into the construction industry as a cost estimator, pursuing an expensive four-year college degree which can range from $30,000 to over $100,000 isn’t the only path to success. Instead, consider enrolling in the MEP Academy Construction Estimator course, which offers a targeted, practical education at a fraction of the cost and time commitment.

This course can be completed in less than six months for around a thousand dollars. This will provide you with specialized skills that are directly applicable to the HVAC and piping industries. By focusing on the specific knowledge and tools needed for this niche, the course equips you to enter the workforce quickly and efficiently, without the burden of student debt. Additionally, the online, industry-specific training offered by the MEP Academy is designed to meet the current demands of employers, making you job-ready upon completion.

In contrast, a four-year degree often involves general education courses that may not directly contribute to your career as an estimator, extending your time in school and inflating costs. With the construction industry increasingly valuing practical experience and specialized skills, the MEP Academy course offers a streamlined, cost-effective alternative that prepares you for a high-paying, in-demand career in a fraction of the time. What are some of the qualities of a good estimator?

Construction Estimator Qualities

The following are some of the qualities of a good estimator.

Analytical skills: Cost estimators need strong analytical abilities to assess various construction and fabrication methods, identifying the most cost-effective options.

Attention to detail: Precision is crucial for cost estimators, as even minor inaccuracies can significantly impact the overall budget of a construction project.

Mathematical proficiency: Excellent math skills are essential for cost estimators to accurately calculate labor, material, and equipment costs for construction projects. While mathematical proficiency is important for cost estimators, the widespread adoption of advanced estimating software has significantly reduced the need for manual calculations. These tools automate many of the complex mathematical processes, allowing estimators to focus more on analysis and decision-making rather than number crunching.

Time management: Effective time management is vital for cost estimators, who must plan ahead and work efficiently to meet strict deadlines.

Writing skills: Strong writing skills are necessary for cost estimators to craft detailed proposals that aid upper tiered contractors or owners in making informed contractor selection decisions.

What is the current job prospect for Construction estimator?

Job Outlook

The job outlook for cost estimators is promising, with the U.S. Bureau of Labor Statistics projecting about 18,000 job openings each year, on average, over the next decade. The steady demand is driven by the ongoing need for accurate cost assessments in construction and manufacturing, as businesses strive to manage expenses and improve efficiency.

The profession offers strong opportunities for those with the right skills. As industries continue to grow and evolve, they require precise cost estimation to ensure project success. These figures are inclusive of other categories besides construction cost estimators. The construction industry is one of the largest contributing factors at about 51% of those employed as cost estimators.

Should you Oversize your Air Conditioner

MEP Academy Instructor

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August 3, 2024

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Should you Oversize your Air Conditioner

The question customers often ask, is should I oversize my air conditioner?

We’re going to show you the difference between an air conditioner that is correctly sized and one that is oversized.

If you prefer to watch the video of this presentation, then scroll to the bottom.

Customers often think that a larger unit will cool their space more quickly, leading to immediate comfort. While it is true that an oversized unit will cool the air faster, it won’t run long enough to evenly distribute the cool air and effectively remove humidity, resulting in discomfort.

A Correctly Sized AC Unit versus and Oversized Air Conditioner

Comparison of Correctly sized to Oversized AC

Here we have two air conditioners, one that is sized correctly at 2-1/2 tons, and another that is oversized at 5 tons. When the thermostat calls for cooling, they both turn on. While the larger unit has the capacity to cool twice as fast, the correctly sized unit will run longer to satisfy the space. You may think this is where the advantage of oversizing makes sense by having a larger unit run for less time. We’ll show you why this is a bad idea.

We have added blue colored dots to represent the moisture level and what happens to the humidity or moisture in the conditioned space when the air conditioner is running. When the air conditioner is running, we can see that moisture is being removed from the air as water begins dripping out of the condensate drain line. The drain line is often out of sight of the occupant who is unaware of its existence unless it becomes clogged and causes a problem.

The oversized unit cools the space so quickly that the air conditioner shuts off before removing enough moisture. We can see the correctly sized unit keeps running while the larger unit has shutoff. The smaller unit runs longer, allowing more time for the moisture in the air to meet the cooling coil and condense out as water. The longer the unit runs the more moisture that is removed from the air, making the air less humid and stuffy.

There are many reasons why you shouldn’t Oversize your Air conditioner

Oversizing an air conditioner can lead to several issues that can negatively impact both the system’s performance and the comfort of the space being cooled. Here are some key reasons to avoid oversizing an air conditioner:

Short Cycling

An oversized air conditioner will cool the space too quickly, causing the system to cycle on and off frequently. This short cycling leads to increased wear and tear on the unit, reducing its lifespan and increasing maintenance costs.

Inadequate Humidity Control

Air conditioners not only cool the air but also remove humidity or moisture. The air contains moisture that isn’t visible to the human eye. Proof of this moisture becomes visible on a hot day with a glass full of ice water. The moisture in the air condenses on the cool outer surface of the glass.

This moisture comes from the surrounding air and not from the ice in the glass. An oversized unit will cool the air so rapidly that it won’t run long enough to remove this moisture or dehumidify the space effectively, leading to higher indoor humidity levels. This can result in a clammy, uncomfortable environment and promote the growth of mold and mildew.

Why is removing moisture from the air so important?

The human body cools itself primarily through the process of sweating and subsequent evaporation of sweat from the skin’s surface. High humidity levels in the environment can slow down the evaporation process because the air is already saturated with moisture. This makes it harder for sweat to evaporate, reducing the cooling efficiency.

Increased Energy Consumption

Frequent cycling and running at a higher capacity than needed will consume more energy, leading to higher utility bills. An oversized unit is less energy-efficient compared to a properly sized one.

Uneven Cooling

Oversized air conditioners can create hot and cold spots within the space. The rapid cooling cycle may not allow the conditioned air to be distributed evenly, leading to some areas being too cold while others remain warm.

Higher Initial Cost

Larger units are more expensive to purchase and install. By properly sizing the air conditioner, you can avoid unnecessary costs and ensure you are investing in the right equipment for your needs.

Environmental Impact

Higher energy consumption results in increased greenhouse gas emissions, which contribute to environmental degradation. Properly sizing an air conditioner helps reduce the carbon footprint of the building.

To determine the correct size for an air conditioner, a detailed load calculation should be performed. Consider factors such as the size of the space, insulation levels, number of occupants, and local climate. This ensures that the system operates efficiently, provides adequate comfort, and maintains a healthy indoor environment.

Should you Oversize your Air Conditioner

Effects of Global Warming Potential on Refrigerant Cost

Can I convert an R410A System to Refrigerant R454B

Can I use my existing tools and equipment on a R32 or R454B system?

Can I use the existing Refrigerant Piping

Space Pressurization

Chemical Fume Hood Flow

Lab Airflow Valves

Fume Hood Exhaust Valves

General Airflow Exhaust Valves

Supply Airflow Valves

Sash Position

Fume Hood Monitor

Duct Pressure and Bypass Air

Lab Exhaust Fan

Summary

Expected Pay

Construction Estimator Job Duties

Education

Construction Estimator Qualities

Job Outlook

Comparison of Correctly sized to Oversized AC

Short Cycling

Inadequate Humidity Control

Why is removing moisture from the air so important?

Increased Energy Consumption

Uneven Cooling

Higher Initial Cost

Environmental Impact

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