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Mission critical infrastructure Part II: Special Engineering Needs of Hospitals and Financial Institutions – Overview of HVAC Considerations

In our last blog, we discussed the Power Considerations of buildings with especially stringent needs for continuous power, specifically hospitals and financial institutions and their data centers. In this blog, we’ll look briefly at the unique heating, ventilation and air conditioning considerations of these industries.

Beyond needing to keep patients at temperatures that are comfortable for them, in hospitals a paramount consideration is of course doing everything possible to reduce the spread of bacteria. Sadly, old systems may be contaminated and spreading airborne contagions to those with the weakest immune system. Modern HVAC systems can reduce this risk. HEPA filtration systems, ventilation and recirculation systems, and targeted air flow systems can all help.

New technologies that involve static heating and cooling built into walls, ceilings and floors do not require forcing air through the building, cutting down on the potential for bacteria to move from one area of a hospital to another.

Other modern equipment can measure air quality, airflow, humidity, pressure, temperature and other factors, and then report and warn when these measurements exceed safe boundaries.

Financial Institutions

The ever-growing computation needs and server density at data centers means increased heat loads on equipment, and need for increased cooling. Hot spots can result in expensive and painful disruptions, so investing in new and superior air conditioning technology is money well spent.

The average data center uses more than 100 times as much energy as any other commercial facility of equivalent size. HVAC accounts for about one-third of the energy use. Some estimates say data centers could eventually use up to 20% of the world’s power supply.

But engineers are working hard to make sure that doesn’t come to pass. There are several technologies for reducing the power consumption of HVAC units in these data centers; and there are also techniques such as keeping aisles of servers separate from aisles that cooling fans draw from, and separating exhaust fans and AC vents. This reduces the energy needed by equipment to cool itself. The system can be enhanced further by situating exhaust fans attached to the building’s ventilation system within the hot aisles and air conditioning output vents in the cool aisles, again keeping these complementary services separate from each other.

And data centers do not have to stay as cool as in years past. ASHRAE has increased its recommended upper temperature from 77 degrees to 80.6 degrees.

But for data centers, HVAC is not just about temperature but humidity. Condensation can harm sensitive equipment, in worst case scenarios, shorting electrical circuits. But some humidity is needed to reduce the potential for damage from electrostatic charges. 45-55% humidity is considered ideal.

Installing an automated control system is another way to curtail the use of HVAC energy. The system can decide to switch off the artificial air conditioning and pull in air from the outside when cool enough. It can also monitor temperatures in multiple rooms to localize cooling or heating.

Taking these extra considerations into account will ensure that mission-critical environments are safe as well as efficient and pleasant to work in.

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Mission Critical Infrastructure Part I: Special Engineering Needs of Hospitals and Financial Institutions

(A large-scale generator for a hospital)

Overview of Power Considerations

Of course every business wants to have full power every day, but for certain sectors, power availability is non-negotiable. Data centers and equipment for hospitals and financial institutions fall into this category. In hospitals and the data centers that serve them, power outages are literally a matter of life and death, while at financial institutions downtime often feels that way.

Here’s a quick look at some key strategies to make sure these types of services are on track to meeting the ideal five nines (99.999%) reliability or uptime.

Uninterruptible Power Supply (UPS) + Standby Power Generators
Having standby power at the ready is the key to ensuring that there are no interruptions to mission critical power. The most reliable system is one that includes, besides the normal utility power, one or more generators, plus  batteries that provide uninterruptible power supply (UPS) for at least the moments of transition between utility power and generator power.

The first step to evaluating a generator system is of course figuring out the energy requirements of the system. Knowing ahead of time the full demand of the entire system, including the type of loads, is crucial to making sure the system will be able to perform as intended during those power outage events. 

Equally important is to decide on how long the system will be designed to operate at full capacity and what type of fuel will be used. This decision will need to factor in code requirements as well as owner’s aspirations and other considerations. For example in New York City, code requires the generator system be provided with “fuel supply sufficient for not less than 6-hour full-demand operation of the system.” However, it is common for generator systems to be designed with fuel supply for a period of well over 24 hours to supply mission critical loads in case of extended power outages.

The start-up power requirements of the generator system will affect unit selection. A major factor in this calculation includes voltage drops at startup which can be significant since this is the point when major motor loads draw the most current (in-rush current). For larger loads, a set of generators may be the best solution, allowing for a staggered start of motors. Again, regulations may dictate the maximum delay in starting times and standby loads.

On the other hand, purchasing an oversized generator adds to the cost of the system and may actually decrease efficiency and reliability, as many generators are not meant to operate at less than 30% of their rated load. Purchasing a system that allows for a steady ramp-up of power, or “walk-in” helps mitigate the chances of loss of power during the transition to generator power, as it reduces the frequency and voltage fluctuations on the generator output.

Another important factor to consider is total harmonic distortion (THD) which can cause the generator to overheat, and create voltage distortion in the system. It is possible to buy a filter to reduce THD, but it’s important to get the right one to avoid the potential for UPS to fail to pick up the load from the generator power. Your UPS and generator must be compatible: the UPS must accept the range of fluctuations in voltage and frequency that will naturally occur when using generator power. If they are not a good match, power will continue to be drawn from the UPS to the load rather than from the generator during a power outage, leading to the danger of depleting the batteries.

To avoid this, an on-line UPS will convert incoming AC power continuously into filtered DC power, and reconvert it back into AC power with a pure sine wave. This will be music to the ears of your sensitive electronic equipment.

Now what if your generator or UPS coincidentally fails to function during one of those power outages events? This brings us to the concept of redundancy. Depending of the business owner’s investment capability, systems can be designed to address such scenarios. For example, one extra standby generator (or UPS) can be provided, similarly sized with the required system and installed in parallel with said system. This is known as N+1 system configuration and provides greater reliability than the basic system.  


For some hospitals, replacing older electrical infrastructure needs to be a priority. The good news is that replacing equipment means less frequent repairs, lower utility costs, increased reliability and safety, reduction and automation of several aspects of maintenance, and often some regained square footage. All of which means fewer headaches for administrators. Investing in modern technology will have a positive impact on both employees and patients.

Financial Institutions

The data needs of financial institutions are vast and vital. Information must flow quickly, without any interruptions. Even a few minutes of downtime during stock market hours could mean the loss of data tracking and action worth millions of dollars. Designing for redundancy and resilience is the key for peace of mind.  Ongoing, diligent maintenance of all aspects of the power system is crucial.

In short, there are many details complex in nature to keep in mind when designing mechanical, and electrical systems for mission-critical facilities. Be sure to consult with a professional engineer such as at DOSE Engineering or other experienced professionals as you look at your options.

Read Part II: HVAC Considerations

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Renewable energy in the United States: Where are we now and where are we headed?

In 2018, U.S. electricity generation facilities generated about 4.18 trillion kWh of electricity. Only about 17% of this was from renewable energy sources such as solar, wind, hydroelectric and geothermal. An estimated 30 billion additional kWh of electricity was generated by small-scale solar photovoltaic systems (like those found on building roofs).

While wind and solar get the most attention, the largest percentage of renewable energy is actually hydropower. Solar brings in under 2% of the nation’s energy.

The production of carbon and the use of renewable energy sources is not distributed evenly throughout the United States. Texas, for example, is the largest producer and consumer of electricity. It provides one-fourth of the nation’s wind power. Three other states account for another one-fourth of wind power generated in the U.S.: Kansas, Iowa, Oklahoma. 

The good news is the overall percentage of electricity generated from renewables has doubled in the last 10 years, from about 8.5% in 2007 to 17% in 2017.

Several states already are well on their way to 50% renewable energy, with Oregon and Washington leading the way with over 40% of their consumption provided by renewable energy. South Dakota, Maine and Idaho are over 30% and Iowa and Vermont are over 25%.

The EIA projects that more states will continue to move toward renewable energy, with 31% of total energy coming from renewable sources by 2050. 

While the current administration is rolling back environmental regulations, future federal and state legislation could increase those numbers. Meanwhile individual states are taking independent action.

Six states and two jurisdictions have set goals to be 100% renewable or carbon-free by 2050 or before: New York, Washington, Hawaii, California, Nevada, New Mexico, Maine, Puerto Rico and Washington D.C. Colorado’s governor has set a goal of 2040, and the state’s largest energy provider is on board for 2050.

Washington state has committed to making the state’s electricity supply carbon neutral by 2030 and 100 percent carbon-free by 2045. The state is the top producer of hydroelectric power in the country; two-thirds of all of the state’s electricity comes from hydro.

Other states which have traditionally relied more heavily on coal have a tougher road ahead. Pennsylvania is the fourth-largest emitter of greenhouse gases in the country but has in recent years, put efforts into switching from coal to natural gas. The state’s governor has said he wants to see an 80-percent reduction in emissions by 2050, and Republican legislators have called for 100% renewable energy by 2050.

New Mexico has enacted a law requiring 50 percent of the electricity provided by the state’s utilities to be generated by renewable sources by 2030, 80 percent by 2040, and 100 percent by 2050.

In addition, 24 states have come together to form the The U.S. Climate Alliance to work to meet the goals of the Paris climate agreement, to reduce greenhouse gas emissions by at least 26% below 2005 levels by 2025.

So while there is still a long way to go, there is clearly momentum driving at least half the states in the nation to reduce their carbon emissions and dramatically increase their use of renewable energy. We will see what the next 10, 20 and 30 years bring!

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How to reduce your building’s carbon footprint to meet new New York City requirements

Following the lead of the New York state government’s commitment to clean energy, the City of New York has passed legislation to do their part to move toward a carbon-neutral future.

The Climate Mobilization Act (1253-2018), a set of bills which was passed overwhelmingly by City Council on April 18, 2019, includes several regulations that affect building owners and developers. The regulations focus on ‘building energy and emissions performance’ and will create a dedicated office within the department of buildings (DOB) whose duties will include, but not be limited to, overseeing the implementation of this legislation within existing buildings, major renovations and new construction alike. Here is an overview of what steps existing building owners (especially of large buildings) in New York City need to take in order to comply with these new mandates.

Since buildings are the source of about two-thirds of New York’s carbon emissions, a big part of the legislation is setting new standards for these buildings. The initiatives aim to decrease greenhouse gas emissions from city buildings by 40% (compared to 2005) in the next ten years, and 80% in the next 20 years. Greenhouse gasses include carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, and others.

This ambitious timeline means energy-efficient retrofits will have to occur on a scale that has never been undertaken by an American city. While there are some exceptions, lengthened timelines and reduced requirements for certain building types, for the most part, any building 25,000 square feet or larger must eventually meet new standards. That’s at least 50,000 spaces in New York.

Buildings that are in the top 20% of producing emissions will only have five years to implement changes. Exceptions include electric and steam power generation plants, rent-stabilized apartments (temporarily), places of worship and non-profit hospitals.

Starting in 2024, owners will need to show that the annual emissions of their building did not exceed the limits set in the law. The limits are based on square feet and occupancy, calculating electricity consumed by the building. Limits are calculated as metric tons of carbon dioxide equivalent per square foot (tCO2e/sf). While certain health care and civic facilities will have limits as high as 0.01193 tCO2e/sf, occupancy groups S and U will have the lowest limits to meet, 0.00110 [limits for years 2030-2034]. For the years of 2024-2029, the limits for a commercial building occupancy group B such as office buildings is set at 0.00846 tCO2e/sf.

According to the Energy Information Administration the average office building used 15.9 kilowatt-hours of electricity per square foot in 2012 (EIA ‘table 3: Total electricity consumption and intensities, 2012’). Using the legislation’s calculations for electricity directly consumed from the utility grid, that works out to 0.00459 tCO2e/sf which is less than the maximum limit of 0.00848 tCO2e/sf mandated, so this seems to indicate that at least for now many modern office buildings will already be in line with the new legislation requirements for the years 2024-2029.

The limits are calculated for those using power delivered by the electrical grid. Those that make use of on-site generation, distributed energy or are not on the utility distribution system will have separate rules. And those using steam will have an easier time meeting the requirements, as the calculations for energy consumed are lower than those for electricity.

By December 31, 2024, building owners must show they have undertaken energy conservation measures, including the following:

  • Adjusting temperature set points for heat and hot water to reflect appropriate space occupancy and facility requirements;
  • Repairing all heating system leaks;
  • Maintaining the heating system, including but not limited to ensuring that system component parts are clean and in good operating condition;
  • Installing individual temperature controls or insulated radiator enclosures with temperature controls on all radiators;
  • Insulating all pipes for heating and/or hot water;
  • Insulating the steam system condensate tank or water tank;
  • Installing indoor and outdoor heating system sensors and boiler controls to allow for proper set-points;
  • Replacing or repairing all steam traps such that all are in working order;
  • Installing or upgrading steam system master venting at the ends of mains, large horizontal pipes, and tops of risers, vertical pipes branching off a main;
  • Upgrading lighting;
  • Weatherizing and air sealing where appropriate, including windows and ductwork, with focus on whole-building insulation;
  • Installing timers on exhaust fans;
  • Installing radiant barriers behind all radiators;
  • Putting solar panels and plants to create green roofs;
  • Use of clean distributed energy resources, including hydropower, solar photovoltaics, geothermal wells or loops, tidal action, waves or water currents, and wind;
  • Using energy storage solutions, such as batteries, thermal systems, mechanical systems, compressed air, and superconducting equipment.

The bill provides for the creation of a loan program for businesses to apply to, to undertake these efforts, and new incentive programs are expected to be created.

It will be possible to purchase offsets or renewable energy credits, for up to ten percent of annual emissions, from authorized, local providers.

The new Office of Building Energy and Emissions Performance will oversee the implementation and auditing of the laws and policies in existing buildings and new construction. That department will be issuing the protocols for monitoring energy use by buildings, and creating an online site for building owners to submit their emissions data.

An Advisory Board will include architects, engineers, a building owner or manager, a public utility industry representative, environmental justice and advocacy organization representatives, a business sector representative, residential tenant representatives and a construction trades representative. A separate commission formed in the legislation has until the end of 2022 to create a guide to delineate the responsibilities of the building designer and owners to comply with emissions limits.

The penalties for noncompliance include fees for emissions above set limits, though there may be some leniency if the owner can show due diligence in attempting to comply by investing in energy efficiency measures. Non-reporting could rack up fines of $25,000 a month or more, while those who lie in their reports could face up to $500,000 or imprisonment. So it’s important to plan ahead, and start early to figure out what steps you will take to comply with the new law. As a building owner or developer, consulting with your architect or engineer for building assessment is a good way to start this process and avoid a lot of headaches down the road.

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Cogeneration: What This Energy  Method Can Do for Your Company

What if you could harness an energy technology that would create not just power but heat for your building, and save you money at the same time?

That technology, called combined heat and power (CHP), or cogeneration, is already being used to produce over 11% of Europe’s electricity. And the technique will only be more widespread in the coming years. China and India have been increasing cogeneration use dramatically, and are expected to keep increasing usage of CHP by up to 28% in the next 11 years.

The process of cogeneration, also known as recycled energy or distributed generation, involves capturing excess heat from whatever production method is used to produce electricity. This could include exhaust from burning oil, coal, natural gas or even biomass or methane from garbage or wastewater. This can happen in a huge power station or a single engine.  

The most straightforward use of this heat is to usher it through pipes to heat various parts of the building. But it can also be used to boil water to create steam to provide an extra power boost. When the latter method is utilized, it’s called combined cycle.

The improvement of percent of useable energy is dramatic. Conventional energy systems convert only about 45% of useable energy from any given fuel source. Cogeneration however, converts about 75% or more, a 60-70% increase in efficiency. CHP technology continues to improve, leading to greater energy conversion and re-use rates.

The benefits are manifold. Buildings that use cogeneration decrease energy use, costs, greenhouse gas emissions and in some cases, pollutants.

While the practice has been widely used in large industrial settings, it is now being used in commercial buildings. Heating and cooling buildings is one of the most expensive operating costs for office buildings, and HVAC (heating, ventilation, air conditioning) is an area that is tailor-made to benefit from cogeneration.

The basic steps to take advantage of cogeneration in a building are:

  • Installing a fuel cell, turbine or engine to generate electricity for the building
  • Installing a heat recovery unit to capture hot exhaust from the electricity generation
  • Using the heat energy to power an absorption chiller or a steam generator, which drives and controls the HVAC system
  • Using any excess thermal energy to heat water for the building’s occupants   

There are thousands of cogeneration plants in North America. While some are utility power plants, many are small plants at corporations, hospitals, hotels or on university campuses. These localized power plants reduce the cost of transporting electricity. Meanwhile, in Japan, Honda is on its fifth-generation of a household-sized cogeneration unit.

Companies are seeing dramatic savings by using cogeneration. Computer networking company Network Appliance uses a cogeneration system with natural gas. The company has said it has reduced energy costs by $300,000 a year to meet its high-demand air conditioning needs.

If you’d like to see more examples of CHP, you can access the Department of Energy’s database of CHP projects.

Of course, you will need to adhere to regulations of your local energy company. New York facilities should read ConEd’s guide to CHP for projects over 5MW.


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Celebrating 10 Years in Business!

We are thrilled to announce this month marks the tenth year since the founding of our company.

Over those years, our work has run the gamut from helping building owners and managers who need to renovate or bring their buildings up to code, to working with people such as architects and commercial real estate developers who want to build new spaces that are not only profitable but also help the greater community. We have worked on both public and private projects, including the new terminal at LaGuardia airport. We have also worked with one of the largest real estate investment and development firms in the Northeast, Matrix Development Group.

Our vision is that of a clean planet, where natural resources are used in a sustainable way to satisfy the needs of all its occupants, and we believe we can help achieve this one project at a time.

“Solving engineering problems and infrastructure issues can ripple out to have a positive impact on people in a variety of ways. Part of finding effective, future-facing solutions for our clients includes putting an emphasis on clean, green energy. We are proud to be a LEED-accredited company,” explains our founder Anostere. He has also worked directly with the City of New York to update its energy code in order to meet its goal of reducing greenhouse gas emissions of 80 percent by 2050.

A recent example is a 975 thousand square foot warehouse in Staten Island, a mixed-use warehouse and office space. As the Engineer of Record for design and planning of the Mechanical/Electrical infrastructure, we incorporated various energy efficient strategies and equipment to help reduce the carbon footprint of the building.

We are very grateful to all our clients for their business, and to our staff and partners for their dedication and hard work. We look forward to several more decades of solving problems for clients in any part of the globe, and having a positive impact on the world!

Anostere Jean
President & CEO
DOSE Engineering

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What does New York’s commitment to clean energy mean for your business?

A couple of months ago, New York’s Governor Cuomo issued a statement that the state would go 100% carbon-free energy by 2040.

This statement follows on the heels of approval by the New York Public Service Commission to implement the third stage of its Clean Energy Standard (CES). Both are part of the state’s Reforming the Energy Vision which sets as goals that by 2030 the state will see a 40% reduction in greenhouse gas emissions from 1990 levels, with 70% of electricity coming from renewable sources like wind, solar, and hydro. They also list as a goal a 600 trillion Btu increase in statewide energy efficiency. By 2080, the plan envisions the State will see an 80% reduction in greenhouse gas emissions.

In December 2018, the state’s Power Authority (NYPA) announced that it was investing $250 million in updating its electric grid to be more flexible to incorporate storage of electricity coming from renewable sources. NYPA already produces most of its electricity (70 percent) from hydropower.

In addition, the New York Public Service Commission has set ambitious energy storage goals of 1,500 MW by 2025 and 3,000 MW by 2030. It also sets a target for energy efficiency for the state’s investor-owned utilities to double utility energy efficiency reductions by 2025. These reductions will come in part from retiring any combustion turbine peaking units in New York City and Long Island that were built before 1990.

But what does all this mean for you and your business? For one thing, the state will be making regulatory changes to utility rates and carbon values. Commercial and industry players should expect to see incentives for switching to renewable offerings by utilities, and for using electricity during off-peak times.

Then there are the dozens of state and federal incentives available to businesses looking to transition to clean energy. Through the state’s  ground source heat pump rebate program for example, a building can get a rebate of up to $500,000 for installing a pump. Another program will help subsidize the installation of a real-time energy management system.

Through the NY Green Bank, commercial real estate owners can get financing to purchase and install “energy efficiency and/or renewable energy assets.”

For data centers looking to invest in energy efficiency equipment and productivity improvements, there’s the Industrial and Process Efficiency (IPE) program which offers performance-based incentives to offset costs. The incentives are calculated from the annual kilowatt-hour savings that result from implementing energy efficiency measures.

And it’s not just infrastructure: There’s a program that supports companies in hiring a full-time On-site Energy Manager, and another to encourage On-the-Job Training for Energy Efficiency and Clean Technology.

You can search this database for a comprehensive list for New York and other states.

New York is joining a trend toward 100% renewable energy seen in other states across the nation. Storage target numbers show this commitment. New Jersey wants to see 2,000 MW by 2030; California’s target is 1,300 MW by 2020; and Massachusetts is looking to dramatically increase the state’s existing 200 MWh storage target to 2,000 MW by 2025.

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Benefits of designing your new building’s infrastructure for flexibility

Recently, a developer client of mine mentioned a planning headache he’s been experiencing. He plans mechanical and electrical infrastructure to meet the requirements for an incoming tenant. But when that tenant moves out, sometimes he rents the space to multiple tenants, who will have new needs and will require redistributing power and separate electrical meters and panels. Conversely, a new tenant may take over the space that was formerly housing multiple tenants.

These tasks can be relatively easy or extremely difficult depending on how the original electrical infrastructure of the base building was designed. In high-turnover commercial spaces for office or retail purposes, this is an especially relevant potential pain point that should be considered in the earliest planning stages.

This brings us to the concept of flexible buildings, also called adaptable buildings. These structures offer the ability for easier maintenance and upgrade over the course of their existence, hence reduction in cost and time expenditures that adaptations require. Flexible buildings provide another benefit: long-term sustainability. If a building can be adapted rather than destroyed and rebuilt, clearly that is better for the environment as well as the bottom line.

Other reasons flexible buildings make sense is that technology continues to change rapidly, and alongside it, tenant expectations for comfortable and safe environments.

Just as office partition systems are created to be flexible to facilitate changes, mechanical and electrical engineering systems can be designed to be modular and easy to swap out as technology and tenant needs develop. In a flexible building, MEP systems are never embedded into building materials. All parts are separately replaceable when their life cycle is complete.

Heating, ventilation, air conditioning and plumbing services in commercial buildings can all be designed to utilize reusable components. Making sure that these systems are easily accessible through floors and ceilings is another important step.

In planning flexible buildings, the key is thinking about the building as two parts: the shell or base building, and the fit-outs or spaces that the base encloses. The base building consists of the concrete foundation, the skeleton, the utility connections and the outer facade. Fit-outs of various sizes can be created and adjusted for individual tenants.

Flexible buildings clearly require being proactive and planning ahead. But the savings of time, money and materials in the long-run make it a very reasonable investment.

Other design strategies include:

  • Using interchangeable system components
  • Increasing layout predictability
  • Using dedicated system zones
  • Separation of parts and modular building
  • Movable elements
  • Easy access to equipment
  • Installing phase systems
  • Reducing inter-system interactions
  • Reducing intra-system interactions
  • Improving flow
  • Enabling sub-systems to be installed or changed with minimal interface issues

You can see a great example of a flexible building by looking at the Solids buildings in Amsterdam. All the vertical pipe shafts and meters are contained in two cores, each of which also contains an elevator and fire stairs. The services access level is several inches higher than the fit-out space to leave room for equipment. Meters and base building utility connections are accessible from the elevator lobby on each floor. A mix of business, residential and community space co-exist within the building.

For tenants, the benefits include freedom to adapt the workspace, determining where walls and even plumbing are placed to meet the needs of their workforce and industry. This ties into the Open Buildings architectural movement, which pushes for the ability to respond to inhabitants’ preferences by offering the ability to adapt individual units or spaces over time.

Flexible buildings are ready for any kind of change: changes in the number and location of people in the building, changes in what the space will be used for, changes in equipment load required, and changes in the outside environment.

We can’t know for sure what the future holds. But both energy and material costs are expected to rise in the future, so planning buildings that will last a long time makes long-term financial sense. And we can be pretty certain that reducing replacement and construction costs will never go out of style.






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Energy Efficient Commercial HVAC Systems: The Latest Technology and Innovations

Creating an energy efficient building involves many factors, but an efficient HVAC system is the key. In my last post, I talked about the money that businesses can save by instituting the latest advances in heating, ventilation and air conditioning (HVAC) systems.

Here are six such systems/technologies, each of which happens to come with its own acronym!

Variable refrigerant flow (VRF)

These systems use refrigerant fluid rather than of air or water. They are by nature ductless. They can be configured to provide different amounts of refrigerant at different times of day and year, and to different parts of the building (zones). This kind of system is best suited for small areas (1,000SF +/-) with limited space for ducts such as in small offices, shops, dwelling units, computer rooms, hotel/motel rooms, schools, banks etc.

Chilled beam cooling (PCB or ACB)

A passive chilled beam (PCB) is a series of tubes containing chilled water. Warm air in a room rises towards the beam on natural convection currents. The air is then cooled before it descends back towards the floor (and occupants of the room). This is quite energy efficient as no fan is required. A variation that uses more power but provides more cool air is called an active chilled beam (ACB). It pulls the air from the space into a cooling chamber and then forces it back into the room. This is still more efficient than moving air across an entire building.

Adjustable speed/Variable Frequency drives (ASDs/VFDs)

These drives save energy as they are able to lower motor speed and torque as load demand decreases. Some motors even have built-in VFDs in the form of microprocessors. These are also called “electronically commutated motors.”

Geothermal heat pumps (GHPs)

These pumps operate a heat exchange with the natural temperature of the ground or water a few feet below the surface depending on site conditions. This is more efficient than exchanging heat with the more volatile temperature of outside air. Ground temperatures in North America are warmer than air in the winter, and cooler in the summer. Moving heat rather than creating it is also more efficient. As a bonus, these pumps are quieter than their counterparts that use air.

Energy Recovery Ventilation (ERV)

These systems work by “double dipping” into the energy that is already being used to exhaust air from a building, transferring heat and moisture from incoming air into the outgoing air. ERV systems are best for buildings located in warmer, more humid climates.

Demand Controlled Ventilation (DCV)

While safety in the form of air quality is of course vital, some systems end up wasting energy by over-ventilating. More modern systems include sensors for carbon dioxide levels, which feed that information to the motors to help determine current environmental ventilation needs.

Electronic expansion valves (EXV)

Here once again is a system that work in the benefit of energy savings. Electronic expansion valves (EXV) is a device that allows for the control of refrigerant flowing through your HVAC equipment, typically the evaporator. As an electronic device, it provides faster, more accurate and steady response to demand of refrigerant flow in the system than the usual thermal expansion valve. This results in the right amount of energy being delivered to the load, hence helping to prevent wasteful usage.


The good news is that these greener HVAC systems usually require less maintenance than older systems. Most of the new systems come with software that tracks equipment use, and will let you know when it’s time for maintenance to keep it at peak efficiency.

Finally, two low-tech maintenance actions that can pay off: Sealing ducts and making sure your building is well insulated are crucial to avoiding the loss of the hot or cold air you’ve worked so hard to bring into the space.

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Why using the latest efficiency technology for HVAC systems could save you tens of thousands of dollars a year

Using energy-efficient heating, ventilation and air conditioning (HVAC) systems isn’t just good for the environment, it’s good for your bottom line.

Several studies have shown that HVAC systems use about half of the total energy use of commercial buildings, and therefore half of energy costs and a big portion of operation costs. Commercial buildings like office buildings, retail spaces and schools consume almost 20 percent of the United State’s total energy. Of these, office buildings consume the most.

The bad news is that from 1979 to 2012, commercial buildings almost doubled their electricity consumption, from 2.2 trillion BTU to 4.2 trillion BTU. The good news is that the efficiency of use in those buildings is improving. A 2012 government report showed an average total annual energy used per square foot of commercial buildings was about 80,000 BTU per square foot. This is down from 91,000 BTU per square foot in 2003, a 12 percent drop in just 10 years. It is expected that those numbers will keep dropping as heating, ventilation and air conditioning equipment improves in efficiency.

Meanwhile, according to 2016 U.S. Energy Information Administration estimates, New York businesses spend $42.35 Dollars a year per Million Btu for retail electricity. That works out to about $3.39 per square foot at the average usage rate reported in 2012. On average, New York companies provide about 125 to 250 square feet of space per office worker. A company of 200 people using 30,000 square feet of space could therefore easily be spending $100,000 in electricity costs.

Indeed, New York commercial businesses spent approximately $11 billion on energy costs in 2016, providing electricity to 545 million square feet of more office space than any other city on the planet.

If energy efficiency were improved by 10 percent, that would save New York businesses $1.1 billion!

The SmartMarket 2016 World Green Building Trends report shows that “green buildings” cost 14 percent less to operate than traditional buildings. For our hypothetical business using 30,000 square feet, a 14 percent improvement would be $14,000 in savings that could be used to invest in other areas.

Therefore it’s not a surprise that demand for green Mechanical and Electrical Engineering solutions is rising rapidly. A recent report predicts that global spending on energy efficient commercial HVAC systems will double in the next nine years, from about $30 billion to $60 billion.

In a future post, I’ll talk about some of those major solutions and systems, and which ones are right for different types of business spaces.

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