Blog July, 2022

“We’re not ready to retire our natural gas just yet!”

(I imagine this will not be popular with the Global Warming/GHG people.)

Blog July,2022  HVAC Design Solutions, Steve Miller, PE

To reduce, and eliminate, the residential use of fossil fuels, it is recommended that everyone switch to electric heat pumps in place of gas furnaces.  Also, to switch from gas ranges/ovens to electric.  And, to switch from gas fired water heaters to heat pump electric water heaters.  And, to switch from gas fired clothes dryers to electric dryers.  Not to mention the recommendation to switch from gasoline powered vehicles to Electric Vehicles. 

Let’s not forget that a large percentage of the electricity to operate the heat pumps and other electric equipment comes from existing power plants.  Those power plants are typically using natural gas or coal (fewer coal plants all the time, fortunately).  After the electrical generation at the power plant, the transmission losses to deliver the electricity to the end user result in as little as 35% of the fuel input being usable at the heat pump.  Whereas the gas furnaces and water heaters in the homes are at least 80% efficient. 

Wouldn’t logic say that the 35% efficient use of power plant gas for the electric powered heat pumps and water heaters would produce significantly more GHG than the 80%+ efficient gas furnaces and water heaters?   

Granted that the inverter-type heat pumps have an approximately 2+ Coefficient of Performance down to about 14 degrees F, meaning they take heat from the surrounding air to add to the electric input to the unit and output 2+ times as much heat as the electrical input.  Typically, however, the COP drops off rapidly below about 10 degrees F, so an electric coil now produces the necessary heat for the building.

Much of the United States experiences nighttime temperatures below 10 deg. F, when there is coincidentally no help from solar panels.  Therefore, all of the heating needs for the building will have to come from the electric grid.  

It will be a long time before the gas/coal power plants are replaced by solar and wind, hydro, etc.  Yes, solar and wind will gradually improve the bottom line, but that will take a lot of time, given the current capacity of the solar and wind installations.  And, when the sun doesn’t shine, and the wind doesn’t blow?  Storage?  Maybe someday storage will be improved, but not yet.

When taking the country as a whole, and the current generation capacity of solar, wind, hydro, etc., if you try to electrify every user, you will soon run out of capacity on the interconnected grid systems.  In the future the renewables will catch up with demand, but in the process a lot of the transmission capacity will have to be upgraded to handle the huge electrical increases.  We better not close the valve on gas yet.

It seems pretty risky to be slamming in all of the electrical appliances, heat pumps, heat pump WH’s, AND electric vehicles, before the infrastructure is upgraded to match the new loads.  Sounds like we are asking for a lot of brownouts and blackouts.  People are so convinced that we should eliminate fossil fuels immediately to save the planet.  I think the “contest” should not be the end-user electrification against the fossil fuel elimination but should be a cooperative effort to improve renewable energy sources and transmission systems.  Otherwise, I think the 25 years target for GHG will become more like 75 years before we can even hope to zero out GHG production. P.S.  It is quite likely that homeowners will have to replace their electric service and change out their 100-amp panels to 200-amp panels if they do upgrade to all electric.  Resulting in a significant expense and long down-time.

Steve M Blog 3/8/22:

Frequently, we get so wrapped up in pressure from project deadlines, pandemics, and world conflicts, that we don’t let our brains have a “vacation”.

With continued pressures, we begin to suffer from fatigue and illness.  We also become prone to making mistakes and being uncooperative in our workplace.  Our brain starts to have traffic jams, with all the negative news and daily pressures.

Having been in the Consulting Engineering business for over thirty-seven years and surviving the occasional 100-hour weeks, I understand the need to sometimes escape from reality.

To help you get your mind away on vacation for a while, I’d like to offer my latest novel: “Finally Found – Stolen Paintings by the Masters”.

“Ray Hendricks was happily retired.  He had been instrumental in destroying a major drug trafficking syndicate and now he was back home with his family.  But he had the unique qualifications that were needed by the DEA and FBI to get to the heart of an even larger cartel that was operating in Mexico and the USA.

An elaborate scheme was developed to allow Ray to infiltrate the organization.  The scheme, conceived by the DEA, involved a specialized Submarine that Ray would “give” to the syndicate in exchange for a small part ownership of their drug trafficking profits.”

My novel is available from Amazon at the following link:

Finally Found: Stolen Paintings by the Masters: Miller, Steve: 9798676637293: Amazon.com: Books

Paperback version is $4.37 (temporary 64% discount!)

Kindle or eBook version is $3.99

Thank you for your time,

Steve Miller, PE  steve@hvacdesignsolutions.com

To: HVAC and Plumbing Engineers and Designers

• Does your QC reviewer always bleed RED all over your “Final” construction documents?

• Do you often miss deadlines because you had too many mistakes or omissions that you had to correct?  (Or do you have to spend long hours to meet those deadlines?)

• Are you frustrated at the lack of coordination between your design discipline and the other design trades?

• Have you missed some critical details in your design that have resulted in large Change Orders?

We may have just what you need to help reduce those problems!

Our “HVAC Design Review Guide” and “Plumbing Design Review Guide” (eBooks or Paperbacks) are specifically designed to address those issues and help you do your own QC checking before submitting as “Final” documents to your QC Manager.

Our Guides are loaded with highly detailed checklists and coordination items that cover most aspects of typical designs.

Check the Table of Contents and example pages at:

Software Packages

Software Packages

Steve Miller, PE; ASHRAE Life Member; HVAC Design Solutions

# # #

Existing Building Upgrades for COVID19 Protection

Most of the existing commercial and public buildings were designed, built, and operated with minimal ventilation air quantities as a primary goal.  That was a logical philosophy, with energy conservation as a major consideration.

Today, we are faced with a more important factor – the safety of the building occupants.  It has been determined that the transmission of the COVID virus (and its variants) is primarily through the air surrounding an infected person.  Apparently, the Omicron variant is a super-spreader in aerosol form.

Existing buildings are being modified on an emergency basis, so people can return to their workplaces.  Typically, that would include “opening the ventilation air intakes to their maximum”, as an attempt to dilute the indoor air with outdoor air.

However … It is quite probable that the air handling systems have not been “balanced” for a long time.  Some of the occupied zones, that are the most remote from the AHU equipment, might not be receiving the outdoor air quantities as desired.

If the building owner/operator wants to assure the tenants or employees that the building is safe to occupy, it is our opinion that a licensed balancing contractor should preform a complete air balancing of the building.

That would require access to a current set of “As-Built” construction documents, as well as a building survey to verify the expected population in each controlled zone.

A key element in the new balancing process would be to assure that the recommended quantity of outdoor air would be provided for each controlled zone.  The recommended “minimum” outdoor air per person is established by ASHRAE Standard 62.1 Ventilation Rate Procedure.

Each controlled zone Total air quantity (from “As-Built” documents) should be compared against the “minimum” OA for each zone.  If any zone’s “As-built” air quantity is less than this “minimum” OA quantity, then obviously that zone would not be getting the recommended OA.

Therefore, each deficient zone’s Total air quantity should be increased to some value above the “minimum” recommended OA quantity, before the air balancing work is undertaken.

During the design phase of the new balancing procedure, each Air Handling Unit cooling capacity should be checked for the ability to increase the Outdoor Air intake quantity.  For the best COVID19 protection, this total OA quantity should be adjusted to the maximum that the AHU can provide, while still maintaining the desired Supply Air Temperature and Humidity conditions.

We have a software program that is specifically designed to calculate the ASHRAE 62.1 recommended OA quantity for each controlled zone.  It is intended to be used for OA requirements of Dedicated Outdoor Air Systems (DOAS).  However, it can be used to establish the “minimum” OA requirements for each zone in any AHU system.  It also optimizes the OA requirement for each zone, based on latent loads, which might increase the recommended OA quantity in some situations.

To use our “62.1 Comply – DOAS” program, the only input information required: Occupancy Category (ASHRAE, built-in), Floor Area, Number of Occupants, and Project Location (built-in climate data for hundreds of locations).  Our program also includes the recommended OA quantity at 130% of “minimum” (which can be used to compare with increased OA at the AHU).

With the output of our DOAS program, the air balancing contractor will have the necessary air quantity values for each zone, to assure that the maximum available OA is being provided for the building occupants.

The description of our “62.1 Comply -DOAS” software package is available at:

https://havcdesignsolutions2.com/software-package/#adoas

Ordering information is available at:

Prices-Orders

Steve Miller, PE ASHRAE Life Member

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COVID-19 and Ventilation Air

“The best solution to pollution is dilution”

Well, maybe not the BEST, but dilution is one thing that reduces the chance of inhaling the virus particles.

For example, consider a room with one cigarette smoker. The air handling system will pick up those smoke particles and pull them into the return duct system. The smoke particles will pass thru the air handler filters, where a portion will be removed from the airstream. The remaining particles will be blown back into the room to add to the smoker’s continuous contribution. The volume of smoke particles in the room will continue to rise dramatically.

Next, consider 100% outdoor air to the air handling unit. Since there is no return, the particles do not come back to add to the smoker’s contribution.

One of ASHRAE’s current recommendations for Covid-19 is to fully open outside air dampers, subject to the AHU’s capability of heating and cooling that extra volume at extreme temperatures. (The OA dampers could at least be controlled to maintain desired discharge temperatures.)

The exhaust air plus relief air capacities might have to be adjusted to accommodate increased OA, unless already set for 100% economizer cooling.

(To be continued)

COVID19 and Ventilation Air (Continuation)

1. A few people have objected to my use of tobacco smoke as an analogy to the Covid19 virus. It seemed like a good visual, but if it offended anyone, I apologize.
2. It makes sense that Building Owners would want to create safe environments, in order to maintain and attract new tenants. It would be hard to put a dollar value on the sense of security that can be achieved, but it seems that it could offset a significant part of the capital expense for modifications to the HVAC systems.
3. Simple and inexpensive changes, like revising OA control to be fully open in moderate temperatures, and controlled by discharge air temps in extreme conditions, could take advantage of any excess htg or cooling capacity of the equipment. If the desired discharge air temp can’t be maintained, then the OA damper can be modulated as required, subject to minimum OA requirements.
4. If control systems include demand-controlled ventilation, occupancy sensor control, economizer controls, or other means of reducing OA, these controls should be disabled or at least modified.
5. Other considerations like improved filters and UV sterilizers should be included, and should be a part of the Building Owner’s bulletins for existing and future tenants.
(To be continued)

8/18/20

COVID-19 and Ventilation Air (continuation)

Expanding on the suggestions for increasing OA quantity and air filtration to the maximum capacity of the AHU equipment:

1. It might be possible to change out the motors on the major equipment, so the heating and cooling capacities can be increased. This could include hydronic pumps, cooling tower motors (if applicable), and air handling units (if the total airflow can be increased). All depending on the Electrical services capacities.

2. Air handling unit filters could be changed out for higher MERV efficiencies. MERV13 filters are available in 2″ thickness, which could be accomplished in most central AHU’s. They are approx. 40% effective at reducing the typical 0.125 micron virus particles. MERV14’s are avail in 6″ and are approx. 65% eff. at 0.125. Both of these changes could require increased HP motors, due to higher static pressure.

3. Increasing OA could also result in increased press. drop at intake devices, such as grilles and louvers, and ductwork, which could also require increased HP’s at the AHU’S.

Ahmed Nasser:

As stated in ASHRAE book ”principles of heating ventilating and air conditioning-8TH Edition- Chapter 4” that Relative humidity has a significant effect on the control of airborne infection. At 50% Rh, the mortality rate of certain organisms is highest (e.g., influenza virus loses much of its virulence). The mortality rate decreases both above and below this value. So from my point of view Keeping The RH is main Factor with the points mentioned above and these points cant do whats needed without Targeting the RH needed in such case

Thanks for your recommendation, Ahmed. We also agree with the effects of RH, and in fact, our DOAS Design software package specifically addresses the RH control, and can adjust for known interior latent loads and local weather data for OA latent. Our program allows you to adjust the leaving air temp from the DOAS unit and the air quantities to each individual interior zone to keep the zone RH at the desired level. https://hvacdesignsolutions2.com/software-packages/#adoas

Steve M, PE

Hasan, We are definitely not experts on filters or filter media. However, the ASHRAE Journal had an excellent article on the subject of COVID19 and filter efficiencies. It is located at: www.nxtbook.com/nxtbooks/ashrae/ashraejournal_RTPOKE/index.php#/p/30

COVID-19 and Ventilation Air (continuation)

Expanding on the suggestions for increasing OA quantity and air filtration to the maximum capacity of the AHU equipment:

1. It is likely that existing office buildings, schools, retail businesses, restaurants, etc. will be required to limit the number of occupants, relative to the numbers that were normal pre-pandemic (possibly only 50% of previous occupants, but on two shifts?).  At least until a proven effective and safe vaccine is widely available.
2. With fewer people in the spaces, the cooling load will be reduced (lower people sensible and latent loads, and lower office equipment sensible loads). These reduced sensible and latent loads can offset some of the increased loads from the recommended larger quantity of OA.
3. If the number of occupants is reduced, updated load calculations should be preformed for each cooling zone. A Test and Balance (TAB) contractor should be enlisted to verify operations and set new air quantities.
4. If the upgrading budget would allow, addition of Dedicated Outdoor Air System (DOAS) units should be considered. The DOAS units should include enthalpy wheels for energy recovery. These DOAS units could significantly reduce the cooling loads on the existing equipment and systems since they will be able to recover some of the sensible and latent cooling from the exhaust or relief air that would otherwise be wasted.
5. If the HVAC systems already include DOAS units, those units should be increased in supply air quantities, up to the maximum recommended velocity on enthalpy wheels and cooling coils. Supply fan motors should be changed out to match new air quantities, subject to Electrical service capacities.

(to be continued)

11/09/2020 Possibilities for a Cover Letter for Engineering companies to present to Building Owners for COVID-19 mitigation

Proactive Approach to the COVID-19 Pandemic

It makes sense that Building Owners and Managers would want to create safe environments in their facilities, so they can maintain current tenants and attract new tenants.  It would be hard to put a dollar value on the sense of security that can be achieved by making their facilities more safe, but it seems that a tenant’s sense of safety could offset a significant part of the capital expense for modifications to the HVAC systems.

Most existing buildings were designed and constructed with energy conservation as a primary factor.  Mechanical ventilation with outdoor air was kept to the minimum recommended quantity during extreme outdoor temperatures.  Heating and cooling equipment and controls were designed to minimize energy consumption and utility costs.

Before the COVID-19 Pandemic of 2020, little consideration of airborne transport of viruses and bacteria was included in building designs, except for hospitals and medical facilities.

Now, it appears that many people are reluctant to go back to their workplace because they fear the potential of contracting the disease from the air they breathe.  They prefer to continue working from home, rather than risk infection at their former workplace.

Our company is reaching out to existing facility Owners and Managers, to offer our services for upgrading their mechanical systems and controls.  We have several remedial options available to reduce the potential of viral transmission in your facility. 

Once these remedial steps are implemented, we recommend that the Owners or Managers utilize these improvements as “marketing” tools and advertise to existing or future tenants that their building has been retrofit to minimize COVID-19 transmission. We would welcome the opportunity to meet with you at your convenience to discuss the possibilities for your facility.

11/09/2020 Possible attachment to Cover Letter to Building Owners

Proactive Approach to the COVID-19 Pandemic

Potential Remedial Actions to Reduce COVID-19 Airborne Transmission.

1. Building survey and HVAC equipment inventory.
2. Obtain existing control sequences for major HVAC equipment.
3. Building “programming” to identify expected occupant levels in each area.
4. Modifications such as increasing OA supply to maximum, depending on equipment capacities
5. Improving filtration to at least MERV13
6. Upgrading equipment to handle increased OA (increase cooling and heating capacities)
7. Revising controls (revise OA controls to maximum equipment capacities)  
8. Recommending balancing contractor involvement
9. Airborne pathogen detection for the COVID-19 virus (for example: Senseware?)
10. Portable air cleaning devices (for example: Sterionizer? bipolar, viruses decreased by 89%, per advertising info.)
11. Cold Plasma air filtration units (airPHX?)
12. Portable HEPA filter equipment additions to all occupied rooms
13. UV-C additions to equipment and/or located at ceiling-level in rooms
14. Add DOAS unit if budget will allow (including enthalpy wheel in the unit, with high-efficiency purge section)
15. Upgrade existing DOAS unit, if applicable
16. Modify relative humidity controls and equipment to maintain 45% to 55% RH in all occupied spaces.
17. Investigate addition of bipolar ionization units in central HVAC equipment
18. If occupant levels are decreased, such as only 50% or 30%, new load calculations should be performed, and existing equipment capacities analyzed.
19. Investigate possibility of replacing motors on existing heating and cooling equipment for increased OA loads

Note: Might not be advisable to include “example equipment manufacturer’s” names.