HVAC Engineering Evanston Chicago, IL 2018-10-29T02:34:59+00:00

What Can Our HVAC Engineers in Evanston Chicago Do For You?

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For more than ten years a great number of real estate investors throughout Smithtown, NY already know that New York Engineers is the engineering company to call when you are ooking for Architectural Engineering in New York. What many local building owners have not realized is the NY Engineers is also your top choice if you are searching for HVAC Engineering services in Evanston Chicago, IL. Those who need more information on what Evanston Chicago HVAC design engineers do? It is an exclusive trade with an an extensive list of obligations. An HVAC design personel will be asked to go through several challenges to solve the underlying issue. This career needs special talent, competence, and the ability to deal with time wisely.

After an HVAC contractor is certified to operate, they are going to be hired by an engineering firm and start to operate many heating, cooling, and refrigeration systems. Their function is always to create new and additional choices according to their customer’s requirements. Every single client will have a unique set of wishes whether it concerns building codes or individual performance expectations. Using all of this material, the engineer sets off on a trek towards making something which is energy-efficient, eco-friendly and ideal for the place it is going to be utilized in – (residential/commercial/industrial). They are generally in charge of the primary creations and overseeing the specific installation.

Generally speaking, an HVAC design engineer in Evanston Chicago will likely be seen working at a design company or in a consulting team based on their numerous years of expertise. Most engineers transition right into a consulting job while they grow older and achieve a better comprehension of what is expected of them.

Comparing HVAC Technician Versus HVAC Engineer

HVAC Engineer and HVAC Technician are often mistaken for one another. Still, they may have different tasks in relation to working with HVAC systems. It’s crucial that you be aware of the difference both as a client also as a professional

An HVAC technician in Evanston Chicago carries a more hands-on job, which implies they are usually seen going to a client’s building to see their present system. They often times take care of the repairs, installations, and overall keep which is needed every now and then. The majority of their job is done together with the customer, which means they must realize how to interact with people properly.

With the HVAC engineer, they are accountable for creating a fresh HVAC system and ensuring that it fits what a client needs. It must fit what the property owner needs whether or not it involves their setup, property, or everything else related to new system. They are also brought in to consult on HVAC creations to ensure things are all in accordance with modern standards. That is why they can find themselves passing time in consulting assignments or at neighborhood engineering companies. That is the difference between those two occupation; HVAC Technician vs HVAC Engineer. There is only so much you can save this page if you would like additional details about the HVAC Engineering services in Evanston Chicago, Illinois by NY Engineers we invite you to take a look at our Evanston Chicago MEP Engineering blog.

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Mechanical Engineers Design HVAC Systems for Sensitive Environments

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A well-designed HVAC system keeps temperature and moisture within a range that is considered comfortable for humans, while constantly renewing the air in a building and filtering out pollutants. Mechanical engineers are, in large part, responsible for ensuring that an HVAC system is operating as it should. The system must also provide an adequate airflow, since stagnant air and draftiness are both detrimental for performance.

In most residential and commercial settings, deviations from the ideal operating conditions are allowable if they are transitory, and there is generally a broad range of acceptable temperature and humidity values. However, there are sensitive environments such as healthcare facilities, where optimal conditions must be kept at all times. Many HVAC systems in less demanding environments are controlled based on temperature only, and humidity is controlled indirectly. However, sensitive environments require that each variable be monitored and controlled independently, and specialized high-performance filters may be required by codes.

Humidity Control in Sensitive Environments

Precise humidity control is typically required for environments with sensitive electronic equipment, healthcare facilities and other similar locations were human life or important systems are at stake. For example, the relative humidity levels for healthcare typically range from 40 to 60 percent:

  • Bacteria and viruses thrive with both low and high humidity levels.
  • Patients who suffer from asthma or allergic rhinitis also experience symptoms in response to humidity extremes.
  • Dry air absorbs moisture from mucous membranes, reducing the body’s ability to fight off infections.
  • Low humidity also increases static electricity accumulation, and discharges can damage modern medical equipment, which is important for medical procedures and generally expensive
  • Dust has a higher tendency to become airborne at low humidity levels, further increasing the chance of triggering allergic reactions.
  • High humidity creates the ideal conditions for mold and dust mites.

Depending on weather conditions, an HVAC system may be required to operate in humidification or drying mode at different times of the year. Some areas of a sensitive environment may have more stringent requirements than others; surgery rooms in hospitals are an example of this. It is the responsibility of qualified mechanical engineers to understand what is needed across various projects.

Air Dehumidification

There are two main approaches for controlling air humidity independently: the HVAC system can use cooling and heating coils in series, or a desiccant wheel can be deployed.

  • Cooling and heating coils: With this approach, air is cooled and dehumidified by the cooling coil until the desired relative humidity is reached. Since this normally results in overcooling, air then flows through a heating coil to raise its temperature back to an acceptable level. This way, both temperature and humidity requirements are met.
  • Desiccant wheel: This device captures air humidity downstream from the cooling coil, and releases it upstream for it to be condensed and gathered. At design conditions, this system does not require any heating input, although a preheating coil is added in case extra dehumidification is required.

Desiccant wheels typically save energy because they eliminate the need for overcooling and reheating. There may be exceptions, however, so it is important to assess each installation independently.

Air Humidification

Healthcare humidification systems are often based on steam, since heating water to high temperatures ensures the destruction of bacteria, especially Legionella. When steam is injected into an airstream, both humidification and heating are accomplished in the same step.

In the most sensitive environments, such as surgery rooms, steam-based humidification is normally required by law to ensure that the system is free from airborne bacteria. Adiabatic humidification is accepted in some sensitive applications, and it provides considerable savings compared with steam systems, although it is necessary to ensure it can be used legally.

Vapor Diffusion Retarders

Vapor diffusion retarders, also known as vapor barriers, complement air drying and humidification systems by providing a barrier against the diffusion of moisture through walls or other elements of the building envelope. Vapor diffusion retarders are classified into three main categories, depending on their rated permeance value:

  • Class I vapor barriers are rated for 0.1 perms or less. Some examples are glass, sheet metal and polyethylene.
  • Class II vapor barriers are rated for permeance values above 0.1 perms but less than or equal to 10 perms. Plywood and unfaced extruded polystyrene are two examples.
  • Class III vapor barriers have permeance values above 10 perms, and some examples are gypsum board, cellulose insulation, bricks and concrete blocks.

The specification of vapor barriers is strongly dependent on weather conditions, and can be especially challenging in northern states, due to how drastically temperature and relative humidity fluctuate throughout the year. Getting in touch with a qualified design firm is highly recommended.

Ventilation for Sensitive Environments: Air Changes per Hour and Filtering

Ventilation systems for sensitive environments must meet specific requirements in terms of air changes per hour (ACH). In surgery rooms, for example, the American Institute of Architects establishes 15 ACH, where 20% must be outdoor air.

  • In a surgery room with a floor area of 600 ft2 and a height of 10 ft, 15 ACH is equivalent to 90,000 ft3 per hour, or 1500 cfm. The outdoor air required would be 300 cfm to meet the 20% requirement.

Filters for sensitive applications must typically meet a minimum MERV rating, and in applications that are especially sensitive compliance with the HEPA standard may be required.

MERV Ratings

MERV stands for Minimum Efficiency Reporting Value, and it is a measurement scale for the effectiveness of filters, which was developed by ASHRAE in the 80s. The scale of MERV ratings ranges from 1 to 16, where larger numbers indicate that the filter is rated for smaller particles and has a higher average arrestance.

  • MERV 1-4: 60 to 80% arrestance, particles larger than 10.0 µm.
  • MERV 5-8: 80 to 95% arrestance, 3.0 to 10.0 µm.
  • MERV 9-12: 90 to 98% arrestance, 1.0 to 3.0 µm.
  • MERV 13-16: Over 95% arrestance, particles from 0.30 to 1.0 µm.

In healthcare applications, filters with MERV ratings of 7 or more are normally specified. In some applications, two filters in tandem are used, where the second has a higher MERV rating than the first.

HEPA Standard

HEPA stands for High-Efficiency Particulate Arrestance, and a filter must remove 99.97% of particles with a diameter of 0.3 µm to qualify as such. It is important to note that the term HEPA has been adopted to refer to any high-efficiency filter, but only those meeting the requirements set forth in the standard are real HEPA filters.

In healthcare applications, HEPA filters are widely used thanks to their ability to capture airborne bacteria and viruses. Once they have been trapped, high-power ultraviolet lights are used to kill them.

It is important to note that higher performance filters also involve an increased pressure drop, raising energy consumption. For this reason, it is important to select a filter with adequate performance for the application, but not over-specified.

General Recommendations from Mechanical Engineers for Sensitive Environment HVAC Design

The most important requirement for HVAC systems in sensitive environments is being able to control humidity and temperature simultaneously, while filtering out pollutants. Therefore, designs based on rules of thumb should be avoided:

  • Sizing air conditioning equipment in tons per square foot of floor area.
  • Sizing ventilation equipment in cfm per ton of HVAC capacity.

Instead, each system must be designed by mechanical engineers to meet a specific temperature and humidity range, as well as air changes per hour and percentage of outdoor air. Hiring the services of qualified engineering professionals is highly recommended to ensure that requirements are met.

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