HVAC UV-C Air System Sanitization

Friday, May 28, 2020

HVAC UV-C Air System Sanitization

I've nearly finished installing a powerful UV sanitizing light in my HVAC system. After I had ordered it I did some investigating. A light this powerful is used to kill pond scum in a pond about ten yards long and ten yards wide and ten feet deep. So it will definitely kill everything in the air system of my home.

Here is the unit I ordered from Amazon.

OdorStop Air Treatment System OS72

I found a relay unit that triggers from 24 VAC and switches 110 VAC. The relay is used to automatically switch the light on when the HVAC blower starts running and turn it off when the blower stops.

For convenience I am using the signal to the humidifier to trigger the relay.

The light unit is designed to run 24x7. It seems to be a waste of watts to have the light burning when the blower isn't running. So I added the switching relay to turn it on when the humidifier water solenoid opens. I may try to switch that. I need to figure out where the signal is that turns on the squirrel cage blower.

IoT Relay

Here is the installation:

There was a dangerous light leak that I had to seal. You can see the shiny tape where the round duct goes into the other duct.

 

I couldn't seal this one. The glow of light is indirect. I checked to make sure it wasn't too bright. I won't look at it. I can glance at it and use it as a convenient indicator that the light is working. The light in there must be blinding.

You can look up the OdorStop on Amazon and watch the video. I wonder if this kills pollen. I know it definitely kills viruses, germs, and fungus.

Now that I know how everything works, if I had to do it again I would get two powerful LED UV screw in bulbs from AliExpress. They cost from $25 to $50 each and last forever. I think they also use about 1/7 the amount of electricity for the same amount of light. I would put them in sockets attached to a plate that bolts into the air duct in about the same way. I would also get a simple solid state switching relay there. It costs about $5. I may do that anyway. These quartz tubes cost about $10 each and should be replaced every year or two.

I hope everyone around you is safe and untouched by the virus. A neighbor is an emergency room doctor. Both she and her husband stayed home for about 8 weeks. I assume they both got COVID-19. This suburban county has about 1,000,000 people. About 10,000 people have caught the disease so far. Right now there are about 1,000 new cases every day. 243 people have died. Having only 1% cases and 0.25% deaths of cases is fairly good. But it could be much lower if our leaders took it seriously. If I get it, depending on how my health is calculated, I have either a 5% or a 25% chance of dying. For me, that is an excellent reason to sanitize the air.

Day Hiking the Appalachian Trail in Shenandoah National Park, November 17, 2018

View West from Skyline Drive

Preparation

For several days I had been dreading the possibility of  the trip, hoping for rain, snow or any inclement weather.  It wasn't the cold or the ordeal that put me off.  It was the possible humiliation of having to quit from fatigue.  I had resolved that no matter what happened, I would proceed at my own  pace, rest whenever I wanted and rest for as long as I wanted.  I hoped that it would help me to endure the ordeal.

The Day Before

I got the bad news.  The weather would be good.  The trails would be open.  There might be some ice on the trails but the roads were clear north of the entrance from the highway, US33. I started preparing for the trip.

It would be a day hike, not over night.  So I would not have to pack a tent, sleeping bag, water purification equipment, a stove, gas, or food to cook. The day pack was ready with all the usual supplies: a trowel, Kleenex tissues, and a water bottle. For the cold weather I had to add a stocking cap, an extra pair of socks, a pair of wool knit gloves, and my new ultra light down sweater. I carefully stuffed the down sweater into its everted left pocket and zipped it up. It made a nice package about as big as a size 15 shoe. It would keep me warm if it turned cold.

In the day pack I also had an extra compass, a headlamp, a flashlight, an emergency signaling mirror, a butane lighter, a large folding knife, a small hiker's Swiss Army knife, a solar cell phone charger, and an emergency first aid kit. The first aid kit was important. It had aspirin, water purification pills, and many other small things that might be needed in various emergencies.

I also had a favorite toy, last year's Christmas present to myself, a titanium solar powered Pathfinder hiking watch. It features a compass, thermometer, barometer, and altimeter. I haven't yet learned to use it well but the altimeter is very useful. Generally, even if you don't know exactly where you are, the altimeter provides a good measure of the effort you have made and how much you have left to make.

Casio Pathfinder Watch

Asolo Boot

I laid out all the clothes I would need: a large hooded windbreaker, convertible pants, a bug repelling shirt, quick dry under clothes, bandana, thick wool socks, and my prize $300 Asolo Italian hiking boots, the best I could find at REI. I added to that my hiking sticks, a hiking hat, and a retainer made from a shoelace to hold my glasses when my nose gets slick from perspiration.
Then I reviewed the maps. I needed an Appalachian Trail map as well as maps of other nearby places in case I needed to divert to an alternative hiking trail.
I set alarms for the following morning. Then I began the arduous process of trying to fall asleep.

 The Next Day

Highway Route To Hiking Area

After showering, dressing, and loading the car, the trip was uneventful. Buy gas. Eat breakfast while driving, drink coffee and listen to the radio. It takes about an hour and a half hour to cross the  plain of the Virginia piedmont from DC to the park. Then it takes another half hour to traverse the winding roads through the mountains to get to the chosen trail head.

Today the plan was to park at the South River Picnic Area and take the Appalachian Trail north for two or three miles then hike back to the car. It didn't work out that way.

Hiking Trail Taken

The trail was not steep or arduous but it was uphill for at least two miles. The total altitude gain was about 600 feet. But because the trail goes up and down over the course of the hike, the actual gain is 1753 feet and the actual decent is 1498 feet. This is the same amount of work as climbing and then descending 163 flights of stairs. But, the rough trail requires you to place your feet carefully. That substantially increases the effort.

According to the Scottish mountaineer William W. Naismith (1856-1935), a smooth trail requires 1 hour for every three miles and another hour for every 2000 feet, gained or lost. 

It took 3:40 to cover the distance. According to Naismith's rule the climb itself, up and down, requires 97 minutes. The distance itself requires 90 minutes. Totaling 3 hours and 7 minutes. That means that slowness, rests, and picking steps through the stony trail consumed another 33 minutes. It is not good but it is not bad either.

Typically Appalachian Trail thru hikers cover about 12 miles per day. Shelters are roughly 12 miles apart.  But there is a lot of variation. If I had been nimbly and briskly hiking this trail at this pace without rests, it would have taken me over nine hours to cover 12 miles between huts. That is a very high bar for me.

Nearing the end of the ascending part of the trail I had the usual perceptions. Over and over again I felt I was nearly at the top of the mountain. Then I would find that another ascent lay ahead. At last the trail crested Bald Face Mountain at 3600 feet. This is a view from Bald Face Mountain Overlook. It is not my photo and not the same time of year.

View from Bald Face Mountain Overlook

The trail began a slow descent and I noticed it was much more icy.  I was now on the north face of the mountain. It had less warmth from the sun. At a certain altitude there were occasional ice needles beside the trail. In order for them to occur the air must be cold enough to freeze water just as it weeps from the ground.

Ice Needles

Waterfall

As I descended I came to a place on the trail where I had to climb down a kind of frozen waterfall about 40 feet high. The trail had been constructed to zigzag down a slope. Unfortunately that path was the only safe path that led down the mountain. And it had been a stream for quite a bit of water before it froze and became ice.

If you imagine something like this, a bit higher, a bit steeper, more narrow, zigzagging, and frozen you will have a good idea how it looked.


Fortunately as a boy I had a lot of experience walking along a frozen creek to get home from school. I could walk on the sidewalks and the street. But I preferred the path through the woods and along the creek.

This frozen waterfall was different. Any fall would have been catastrophic. I reminded myself, over and over again to proceed slowly. I had four contacts with the ground: two hiking sticks and two feet. I made sure that they were all planted firmly and I only moved one of them at a time.

Pocosin Cabin

I descended further, passing by a picturesque trail hut built of stone. It was padlocked. Then I went on to Skyline drive to hitch hike back to the car. Several cars passed by but a friendly park ranger stopped to give me a short ride back to my car. He also ran my driver's license and my plates, just to make an indelible record of his activities.

Dog Rules

"Yudhishthira said, ‘It has been said that the abandonment of one that is devoted is infinitely sinful. It is equal to the sin that one incurs by slaying a Brahmana. Hence, O great Indra, I shall not abandon this dog today from desire of my happiness. Even this is my vow steadily pursued, that I never give up a person that is terrified, nor one that is devoted to me, nor one that seeks my protection, saying that he is destitute, nor one that is afflicted, nor one that has come to me, nor one that is weak in protecting oneself, nor one that is solicitous of life. I shall never give up such a one till my own life is at an end.’

-- The Mahabharata, Book 17, Section 3

Over the ages dogs have adapted to mankind by showing personalities that men view as the most noble. We can learn much about the best conduct in personal relationships if we study the simple personality adaptations that have been made by dogs.

If we look at our relationships from the simple point of view of a dog we can see a brief and simple set of rules for survival and adaptation in nearly any human social setting.

Rules:

1. Never get angry with your master. Don't criticize your master. Try sincerely to trust your master.

2. Jealously protect your master from any possible threat, especially other dogs - like you.

3. Always show gratitude and joy to your master.

As time passes

I wonder at the immensity of creation.
We are smaller than grains of sand
In the vast ocean of time and space.

What is the purpose in giving thanks
When we are so small?

Is it for another or is it for ourselves?

When we know there is something vast
Beyond ourselves
We can free our grasp of personal interests
And help others.

That is the basis of culture and civilization,
The thing that transcends our own lives,
And makes us humans instead of animals.
Among all living things, it makes us unique.

We carry it with us in our conquests.
We teach it to our children.
We breed it into our dogs and horses.
Giving them what we feel is most important and noble.

But more than that
It gives us the peace of heaven.

We can leave this life without fear,
Knowing that the important things
Will continue on,
Like the immensity of time and space.
We are smaller than grains of sand
In the vast ocean of civilization and history.