Posted on Thu, Feb 09, 2012 @ 03:39 PM
Eric Baluch
ebaluch@tesengineering.com
Expansion tanks are used in closed loop hydronic systems, such as in boiler systems or chilled water systems. In closed loop piping systems, when the fluid temperature rises, expansion of the fluid occurs. In boiler systems, the water is brought in cold and is heated by the boiler causing expansion. If a chiller is turned off within a chilled water system, the temperature of the water will rise. Expansion tanks allow expansion and contraction of the fluid within these systems without damaging components of the systems by regulating the pressure of the fluid in the system. Without an expansion tank the pressure would rise and blow pressure relief valves.
There are three main types of expansion tanks used:
The first is a plain steel tank that is open to that atmosphere. In atmospheric expansion tanks, the water and air in the tank are in direct contact. Smaller models of atmospheric tanks can cost less than other styles of expansion tanks due to their simplicity. Atmospheric expansion tanks can also withstand higher temperatures than other expansion tank types because there is no rubber barrier in the tank. The plain steel expansion tank can be purchased with the ASME option, ensuring higher pressure ratings and quality. However, plain steel tanks also have a higher installed cost because they are much larger than other tank types, often requiring them to be mounted from the ceiling of a mechanical room. Plain steel tanks have higher maintenance costs. The level indicators that are required for the atmospheric tank often develop leaks that force air out of the tank and the tank eventually is completely filled with water, leaving no room for expansion. Corrosion within the system can occur because air on the atmospheric side of this type of expansion tank is dissolved in the water, causing rust in the pipes.
The second type of tank is a bladder style tank. In a bladder tank, there is a rubber bladder that expands and contracts as fluid expands and contracts within the system. In bladder tanks, there is no direct contact between the air in the tank and the fluid in the bladder which will reduce corrosion compared to a atmospheric tank. Bladder tanks can typically fill 100% with fluid, reducing the size of tank needed. The bladder is typically removable and/or replaceable allowing for simpler and less expensive repairs or inspections. Bladder tanks also have an ASME option available. They can also be floor mounted in the vertical position which can save valuable space. Bladder tanks can also be purchased with FDA approved Butyl bladders allowing for use in potable water systems. However, bladder tank usually have a higher initial cost and have a lower maximum allowable temperature than plain steel tanks because of the material of the bladder.
The third type of tank is a diaphragm tank. In a diaphragm tank, there is a diaphragm that separates the fluid in the top of the tank and the air in the bottom of the tank. Diaphragm tanks are similar to bladder tanks in that there is no direct contact between the fluid and air in the system, which reduces corrosion. Diaphragm tanks require less maintenance and have a lower installation cost. They can be floor mounted in the vertical position to save space and also come with an ASME option. Unlike bladder tanks, diaphragm tanks have a limited acceptance volume, requiring a larger tank. The diaphragm is not replaceable and the diaphragm tank has a lower maximum temperature than the plain steel tank because of the material of the diaphragm.
Posted on Fri, Jan 27, 2012 @ 09:45 AM
Sarah Douglass
sdouglass@tesengineering.com
Ohio Building Code has adopted the Americans with Disability Act Accessibility Guidelines (ADAAG) as part of code in order to ensure that areas of rescue assistance are required in any building that is more than one story tall. Areas of rescue assistance are spaces within a building that persons with disabilities who are unable to exit the building using the stairs can be safe while waiting to be rescued from the building. According to ADAAG 4.3.11.1, an area of rescue assistance can be one of the following:
1. A portion of stair landing within a smoke proof enclosure
2. A portion of a one hour fire resistive corridor adjacent to an exit
3. A vestibule located adjacent to an exit enclosure
4. An area or room separated from other portions of the building by a smoke barrier
5. A pressurized elevator lobby
Code requires a building each area of rescue assistance to provide two accessible spaces, not less than 30”x48” and not encroaching on exit width. The areas must be near the normal paths of egress, but cannot prevent those using these paths from exiting properly.
ADAAG 4.3.11.4 also requires each area of rescue assistance to have access to a two-way communications system. The method of two-way communications, with both audio and visual signals, shall be provided between each area of rescue assistance and the primary entry. The communications system requires the following:
1. The communication system must report to a primary entrance.
2. There must be a sender/receiver at both the primary entrance and each rescue area.
3. The primary location must indicate where and which rescue area’s sender/receiver has been activated.
4. The communication system must have a battery backup or be connected to the Life Safety System Power.
Requiring areas of rescue assistance in buildings benefits both people who are disabled and the fire department. People who are disabled are kept safe while waiting for rescue, while the firefighters are able to pinpoint where they need to go for a rescue as well as the number of people they will be rescuing.
The engineers at TES Engineering are well versed in this and many other Americans with Disabilities Act topics across different states. Contact us today.
Posted on Fri, Jan 27, 2012 @ 08:49 AM
Roger Hauser
rhauser@tesengineering.com
An independent review of Tenant MEP drawings can protect the owner’s investment by ensuring compliance with current mall MEP systems - generating long term cost savings, quicker move-ins, and fewer construction issues. Our drawing reviews help the Landlord confirm a comfortable shopping experience is achieved for the customer.
In central plant malls, many tenant engineers design plans to get “chilled media (air or water)” based on an irreverent corporate-mandated criteria such as 1.5 cfm per square foot in VAV malls and 1 gpm per 100 square foot in chilled water malls, regardless of tenant’s HVAC load calculations. Even worse would be a stipulated requirement in rooftop unit terms of 250 square feet per ton because this criteria doesn’t easily translate into central plant terms.
A basic review of tenant’s drawings will validate the HVAC equipment is sized in accordance with actual tenant HVAC load calculations. A simple clause in the lease agreement stipulating that the tenant’s plans must meet MEP tenant review approval will protect the mall from a tenant who has instructed their engineer to design based on an arbitrary load resulting in over sized equipment or worse, overstated requirements from the Landlord’s central plant. Let the MEP reviewer verify the tenant’s equipment is sized to handle its actual load and maximize mall system efficiency.
TES Engineering has experienced Tenant Coordinators and MEP Engineers who work together to be sure your tenant fits into your building properly.
Posted on Thu, Jan 19, 2012 @ 10:15 AM
Sarah Douglass
sdouglass@tesengineering.com
ASHRAE 90.1 requires any building larger than 5000 square feet have interior lighting controlled to shut off in all spaces automatically. Examples of an automatic control device include a time-of-day device like a time clock, a central lighting control signal, an energy management system, or an occupancy sensor. Occupancy sensors are one of the most commonly used devices for controlling interior lighting and meet the requirements of ASHRAE 90.1.
Passive infrared (PIR) occupancy sensors sense heat and motion in a space and adjust the lights accordingly. These sensors require a direct line of sight and have a limited sensitivity of 15 feet or less. An alternative to this type of device is ultrasonic sensors. They emit a high frequency signal that senses sound and motion. These sensors are able to see around corners and objects, allowing them to have coverage up to 25 feet.
High-mounted sensors are another option and can be mounted on the ceiling, high on the wall, or in a corner. These are used in large areas that may contain obstacles, corridors, or aisles. These sensors are 2 to 3 times more costly to install, but are very economical if used to control several large zones.
Wall-mounted sensors are usually used in small, enclosed spaces since they require a direct line of sight between the sensor and the task area. These sensors are inexpensive and very easy to install. Workspace sensors are used in individual cubicles. They are connected to the power strip within the cubicle and are used to control lights as well as plug in loads such as radios or heaters.
Small spaces may only require one sensor while larger areas may need several sensors, each covering a different own zone. Coverage zones of a large area should overlap by 20% in order to ensure the system will not result in false on/offs. Each sensor has adjustable time delays and sensitivities, allowing the coverage system to be customized to the space it is in. Time delays of 15 minutes are usually recommended and sensitivities must not be set too high or else the sensor will pick up changes that do not require the lights to turn on.
Choosing the correct sensor and technology are very important when using occupancy sensors to control lighting within an area. TES Engineering is happy to assist you with your next lighting project. Click below to talk with an engineer today.
Posted on Wed, Jan 11, 2012 @ 02:20 PM
Understanding and exceeding clients’ expectations is what TES Engineering has always been trying to achieve.
This month, we are excited to introduce a new tool that will enable us to gather feedback from you, our most valued customers.
While you are working with TES, we may ask you to complete a request for feedback. This is your opportunity to tell us how successfully your project is being completed and identify areas for improvement.
In-depth, up-to-date information will allow us to comprehend our performance more effectively and will ensure our engineers are providing the most accurate and efficient services possible.
TES has teamed with Design Facilitator, a premier client feedback firm, to develop and administrate our surveys. Please look for these surveys in coming weeks.
If you have any questions, please contact us for more information.
We sincerely value your opinion and look forward to your feedback.
Posted on Wed, Jan 11, 2012 @ 02:04 PM
Steven George
sgeorge@tesengineering.com
Over the years, lighting options have changed. These changes have resulted in more cost efficient, more energy efficient, and longer lasting options for homeowners and businesses.
Incandescent lamps are the most traditional option. Many homes contain these lamps in 40, 60 and 100-watt varieties in an array of different applications - from desk lamps and closets to hallways and stairs. They can be purchased cheaply, although availability is becoming limited due to a restriction by government regulations.
Wasted energy is a problem with incandescent bulbs. The inefficiency results from a high-burning metal filament inside the bulb that spends an enormous amount of energy creating light, but also creates heat. Compact Fluorescent Lights (CFLs) are more energy efficient than incandescent bulbs because there is no burning filament. A 15-watt CFL uses about $75 of electricity a year and produces the same amount of lumens as a 60-watt incandescent bulb which would cost about $300 of electricity in an average office application.
The lack of a burning filament also means the CFL lasts 8 to 15 times longer than incandescents. CFLs typically have a rated lifespan of 6,000 to 15,000 hours, whereas incandescent lamps are usually manufactured with a rated lifespan of 750 hours or 1,000 hours. The downsides of CFLs are their mercury content and associated high cost of disposal.
Light Emitting Diodes (LED) lamps are the newest and arguably best option for homes and businesses. To achieve the same lighting potential as a 60-watt incandescent bulb, LEDs use just 8 watts of power, costing a consumer only $30 per year. These bulbs also last an average of 50,000 hours or longer. LED lighting is also used in decorative applications, like in areas where lighting needs to alter between different colors, because it can be changed electronically. A drawback to LED lighting is its high initial cost, a factor that can be offset by low power usage and extremely long life.
Lighting options are constantly changing and improving. Stay tuned to TES Engineering for dependable guidance on this issue, as well as other exciting topics.
Posted on Thu, Nov 10, 2011 @ 02:31 PM
written by: Sara Lewis | slewis@tesengineering.com
TES Engineering recently completed an exciting energy-focused retail design project with J.C.Penney Company, Inc. in Dallas, Texas. The new JCPenney store exemplifies the benefits of increased collaboration that starts at the initial phase of design and continues throughout the entire process.
Because JCPenney set a goal to create one of the most state-of-art, environmentally conscious retail stores in the country, collaboration for this particular project was even more important than usual. TES Engineering’s energy engineers worked closely with architects and designers as TES introduced new technology that improved the store’s aesthetic appearance and merchandising power.
To achieve the maximum amount of energy savings and the minimum amount of environmental impact, it is necessary for the design team to work together. Changing an element such as roof insulation can drastically affect the HVAC system, which changes building energy use. Interrelationships like these were discussed and considered before changes were implemented.
JCPenney pushed the design team further with the challenge to be 50% better than the ASHRAE energy standard. Energy-saving design elements included energy recovery ventilators, LED lighting, and demand-controlled ventilation sensors. This JCPenney store uses 36 percent less energy than a typical location, uses 58 percent less energy than a generic retail store (code required), and uses 67 percent less energy than other retail stores in Energy Star’s Portfolio Manager. The additional costs associated with the green building have an 8.8 year payback.
Elements that were ruled out:
+ Skylights on sales floor - increased heat gain counteracted energy savings
+ Thermal ice storage - HVAC system includes multiple fan speed settings
+ R-40 roof and R-30 wall insulation - increased insulation didn’t offer cost-effective payback
Elements that were included:
+ Skylights and daylight harvesting in office and stock areas - skylights and day light harvesting fit energy usage profiles for these areas
+ Energy recovery ventilators - reducing outside air load provided energy savings
+ Demand-controlled ventilation controls and sensors - reduced outside air when appropriate
+ R-28 roof and R-19 wall insulation - determined to be optimum level of insulation
+ LED Lighting Design - on sales floor to maximize effective lighting and reduce energy usage during the long hours of operation
TES Engineering was excited to have been part of a great team and involved in such a revolutionary retail project.
Posted on Thu, Nov 10, 2011 @ 01:47 PM
written by: Bob Catino | bcatino@tesengineering.com
Determining electrical component capacity is more complicated than it initially appears. Let’s take a look at the following scenario:
One day, your office receives a call from a leasing agent representing a luxury retailer. The agent indicates this retailer is interested in your property, if you can guarantee them 400 amps at 277/480V electrical service.
A quick response is required; you immediately begin investigating using a combination of your experience with electrical system and existing tenant and building information.
You find legible base building plans that clearly show the landlord’s electrical distribution equipment is 1200 amp at 277/480v and a list of original tenants’ connection sizes.
Using this information, you compare the current lease plan to the tenants listed on the distribution equipment. You continue your due diligence by researching tenant drawing files to confirm the sum of current tenant services. It would not be unusual for this sum to be far larger than the service size, even double the service size in some cases.
You say to yourself, “Wait a minute. How can this be?”
As straightforward as this calculation may appear, simply adding the tenants’ disconnect switch sizes together will not determine the value needed. Typically, the actual demand load of a Tenant is less than 50 percent of the circuit ampacity of the switch. If a tenant has a 200-amp service, the actual load is usually much closer to 100 amps.
Empowered with a bit more knowledge, you continue this investigation. You can divide the original total figure (1800 amps) by 2, given the new information, resulting in 900 amps. Also, divide the requested 400 amps in half, also. We arrive at a total of 1100 amps, giving you confidence to tell the leasing agent on the phone that it appears there’s adequate power.
Please exercise caution when using this rule of thumb methodology as it can lead you astray at times. TES Engineering can apply more detailed research and connected load calculations to more confidently say the landlord’s main service can usually accommodate additional without increasing service, but that’s usually when the lease negotiations get further along. A key point to the above scenario is that adding a tenant to a landlord’s electrical gear is not always expensive if you are able to do a little bit of basic research.
Also, consider this: building officials, plan reviewers, and inspectors are increasingly requesting landlord/tenant electrical utility tracking. Tracking establishes a current record of electrical loads, making them invaluable for day-to-day discussions and an asset when presented with important opportunities.
TES Engineering regularly assists tenant coordinators with electrical capacity issues. Contact one of our tenant coordinators or electrical engineers today for dependable guidance.
Posted on Thu, Nov 03, 2011 @ 10:32 AM
Joe Weagraff, Marketing Coordinator | jweagraff@tesengineering.com
On October 28th, TES Engineering attended the Cleveland State University Career Fair. Hilmi, Sara, and I had many excellent discussions with a wide range of candidates - from freshman undergraduate students to seasoned engineering professionals - all of whom had an interest in Mechanical and Electrical design for the building and construction industry.
TES is pleased to maintain our strong relationship with Cleveland State University. We employ a number of CSU alumni members with a strong educational and professional network that will help sustain our company's continued growth. We're looking forward to attending the next event.
Below are a few photos from the CSU Career Fair:
Posted on Wed, Oct 26, 2011 @ 10:21 AM
Joe Zaworski | jzaworski@tesengineering.com
When the term degree-days appears on your gas bill, you may wonder what the term means and how the figure was derived.
We apologize, but before we define degree-days, we need to define balance point.
Another tool useful in understanding how weather can effect energy consumption is a building’s balance point. Simply, the balance point for a particular building is the outdoor temperature at which the building does not require any heating or cooling. It’s kind of like the tipping point of a scale, with heating energy on one side and cooling energy on the other.
The building’s balance point is determined in graphical form as a function of energy consumption and ambient temperature. Fitting a trend line to this utility data allows one to determine when a building requires either heating or cooling.
Degree-days are the sum of degrees above or below a building’s balance point temperature in a given period of time, most commonly a day, a month or a year. The cooler the weather is, the more heating degree-days there are (resulting in increased demand for heating energy). The warmer the weather is, the more cooling degree-days there are (resulting in increased demand for cooling energy).
While this number can determine weather-related patterns in heating and cooling usage, at the same time, it alerts one to problems with older HVAC equipment or energy savings impact of new HVAC equipment. With historic degree-day data in hand, it will be easier to identify anomalies in building operations and malfunctioning controls or equipment.
When looking at a gas bill, one can see the amount of gas-consumed correlates with the number of degree-days in that month. To ensure the building’s equipment is operating correctly, verify the higher consumption relates to more degree-days.
Degree-days and balance points are two useful tools to track demand for energy used by heating or cooling equipment. For more information concerning degree-days, balance points, or general facility operations, contact TES Engineering.