So I was on here for a while last night researching lighting. It seems the consensus is that the two main drawbacks of HID is heat and energy.
The heat isn't a big deal for me as I live in Idaho, and the winters here are brutal, which brings me to my first question:
How much heat do these things give off? I'm growing in a garage that I will insulate - will they give off enough to heat the garage?
My second question is on the energy. How much do these cost to run? I know it depends on how much you pay for electricity, but ball park-- I'll be running 3 of the 400w, what could I expect?
Thanks!
Phil
Tags:
I figured out the answer to the energy. You can use this formula to calculate the cost:
number of watts x number of hours per day x days in the month, then divide that number by 1000. Take that number and multiply it by your cost per kw/hr.
So, for me, 1200w x 16 hours x 30.5 days = 585,600
585,600 / 1000 = 585.6 x .0595 = $34.85
Still tho, how hot do these things get? Will 3 of these heat a 187sqft space?
Here's a handy cost to run calculator I linked (can't remember exactly where) for us lazy folk...http://www.citytrf.net/costs_calculator.htm
Are you thinking of running digital or magnetic ballasts (I can attest to magnetic ballast getting really friggin hot, but I can use that heat), since the ballasts themselves will also help to heat the space up.
BTW, good choice going with HID's...If you run the numbers (lumens per Watt, coverage area, penetration, bulb replacements and all) I think they are actually the cheapest and best route...
I don't know how cold it gets where your at, or how well insulated your space will be, but those lights should DEFINITELY help heat that 187 sq.foot space up. Just don't forget how important ventilation still is (even if it sometimes runs counter to your heating needs). You may, or may not be able to get something useful out of these blogs? Hope something in there helps. (I wasn't able to find any info on the topic, so I kept meticulous daily notes on some half-assed 'experiments' and posted the 'run down' here...
http://aquaponicscommunity.com/profiles/blogs/greenhouse-heating-us...
http://aquaponicscommunity.com/profiles/blogs/greenhouse-heating-us...
Thanks a lot for all of the info Vlad. I'll take a look at those blogs. As far as digital or magnetic, I'm thinking digital.
Wattage is a measure we can use as an input into our Aquaponic system/structure. BTU is a measure of heat energy. And 1 watt-hour is equal to 3.413 BTU. No mattter how a watt of electrical energy is used within a structure or system,1 watt-hour is equal to 3.413 BTU.
Knowing the total size in area and volume, and total wattage used, one can calculate how much temperature rise or fall may be experienced.
You may also note that Each Horse Power used = 746 Watts
Thanks Glenn, but according to the formula, running 3 400w lights would raise the temp over 2300 degrees per hour. That doesn't seem right. Are these things really that hot?
Math is not one of my strongest subjects, so it's quite possible I did something wrong.
I'm sorry I don't know which formula you mean. But yes 1200 watts is a lot of energy relatively speaking and unless the heat has some larger area to displace into or dissipitate, temperature could rise quickly. What volume of area( in cu. ft.) were you thinking?
Another way of thinking about it is a 1500 watt water heater can heat 30 gal. pretty quickly with no flow. if that were through a 30 gal storage area at 100 gpm then, depending on how much dissipitation went on else where in the flow path,,, a large greenhouse grow space for instance the water could seem to take forever to warm.
I'm not sure either what formula you are using, but it doesn't seem right (or at least not applicable to your scenario, you want to know how much they'll heat up the volume of air you have in your garage, and not how hot the spaces inside the bulbs get, or whatever). You will be very, very, VERY hard pressed to find a formula for doing that, and a lot of it will be interdependent on other factors (things like... say, at ambient air temps of 0Celsius your 3 bulbs will heat up the air to 20Celsius...So you then say"aha, these things heat the air 20 Celsius units". Well that's only true when the ambient air temp is 0Celsius.
If abient air temps are say -10Celsius your same bulbs may only heat the place up to say, 3Celsius NOT 10Celsius like you'd expect...giving you a gain of only 13Celsius units... the colder the ambient air gets the harder time the bulbs will have keeping up so to speak. Conversely, if ambient air is +5degrees the same 3 bulbs might heat up the air MORE than the 20Celsius units you noticed at 0 degrees. Make sense?
Please don't get caught up on those exact numbers above as I just pulled the numbers themselves out of my ass, but they do describe one of the general trends I noticed this past winter. I do have (I kept a note book) notes with exact numbers from this past winter where I measured temps 3 times a day/night in a specific volume of space, heated with specific types of lights, and compared that to air temps outside the insulated space, and that is one of the trends that I noticed while looking at the numbers and observing what was going on...That's kinda what those 2 blogs are about. Really you'll just need to try it out and see. I'd suggest creating a "space within a space" in your garage (I think I said that in the blog too :) with some plastic sheeting esp. in the brutal winter months. (The lights being inside that plastic sheeting space along with plants of course)...If it gets too hot just add more ventilation to let more cold in (can be as easy as un-duct taping the flap that you use for the "door" to get in there, or turning on a little fan...nothing fancy.
You'll figure it out. It's way easier if you don't over think it. (Which is what I was probably doing at one point). I just sort of guesstimated based on some previous observations, and then just did it...and it worked out almost perfectly to my surprise. (One of the things that I did underestimate though was just how much heat the old T-8's fluorescents actually produce...Now the tubes don't feel hot under your hand, which is what most people get caught up on (causing them to say incorrectly that a T-8 fixture "doesn't put out much heat"...that's total bullshit, because if you put one in a closed space that space will get significantly hotter. We never think about how much heat the T-8 ballasts are putting off, nor about the actual heat coming off the entire length of the tube, we just think about the 'little bit of' heat coming off the small point where our finger is under).
Phil Bowyer said:
Thanks Glenn, but according to the formula, running 3 400w lights would raise the temp over 2300 degrees per hour. That doesn't seem right. Are these things really that hot?
Math is not one of my strongest subjects, so it's quite possible I did something wrong.
Glenn, The standard unit for the rate of heat transferred, is in fact the WATT. So no reason to complicate things by converting to BTU's...Unless you Americans are dead set on it
Glenn said:
Wattage is a measure we can use as an input into our Aquaponic system/structure. BTU is a measure of heat energy. And 1 watt-hour is equal to 3.413 BTU. No mattter how a watt of electrical energy is used within a structure or system,1 watt-hour is equal to 3.413 BTU.
Knowing the total size in area and volume, and total wattage used, one can calculate how much temperature rise or fall may be experienced.
You may also note that Each Horse Power used = 746 Watts
Thanks for the repys Glenn and Vlad.
So, my biggest concern is winters. We can get pretty cold where I am, and being new to all of this, I want to make sure I keep the proper temperature. I don't want it to get too hot, or too cold - so I wanted to know what to expect for the winter and how to handle that heat and how I would handle it during the winter if it was too much heat.
I have a very tight budget, so I want to do it right the first time. Winter's a few months off (I think, we actually got about 3 inches of snow the other day) so I think I'll take your advice Vlad, and not over think it, just keep track of it during the summer and fall and kind of just see what happens.
I appreciate both of you guys helping me. As I said I'm new to this whole thing but jumping in with both feet. The more I learn the more I realize how much there is to know. Thanks a ton!
And Vlad, I didn't get to those blogs yesterday, but they are on the list for today.
Vlad. Most American.s aren't dead set on anything these days. I however as an electrician will keep to my standards and you can certainly keep to yours. In mine, Mr. Ohm held that P=I* E where P was watts. Maybe you would like to meet in the middle and use joule. I don't care. Power is power. energy is energy. measured in volume, rate, or potential is the difference.
Vlad Jovanovic said:
Glenn, The standard unit for the rate of heat transferred, is in fact the WATT. So no reason to complicate things by converting to BTU's...Unless you Americans are dead set on it
Glenn said:Wattage is a measure we can use as an input into our Aquaponic system/structure. BTU is a measure of heat energy. And 1 watt-hour is equal to 3.413 BTU. No mattter how a watt of electrical energy is used within a structure or system,1 watt-hour is equal to 3.413 BTU.
Knowing the total size in area and volume, and total wattage used, one can calculate how much temperature rise or fall may be experienced.
You may also note that Each Horse Power used = 746 Watts
My apologies Glenn, I thought we were talking about heat. Meeting in the middle sounds good though. In the realm of heat transfer; one joule per one second, equals one watt...I just bought a propane heater unit for the greenhouse, it is rated at 31.2 kW...(that's roughly 106,500 BTU's or, 26,800 kcal/h). I don't really care either, just that some of those old Imperial units sometimes confuse me...way to many strange numbers... example:
A BTU is defined as: " ...the amount of energy it takes to heat up 0.1198 US Gallons from 39F to 40F (3.8 degrees Celsius to 4.4 degrees Celsius).
Compare that to the other standard for heat which is: "...1 joule per second = 1 watt..."
I'm not a real genius with the numbers either (like Phil said), so obviously the watt standard is easier for me.
Yep, even our car engines are rated in Watts...
I like you, am a big fan of the Watt, and not just for electricity either.
Glenn said:
Vlad. Most American.s aren't dead set on anything these days. I however as an electrician will keep to my standards and you can certainly keep to yours. In mine, Mr. Ohm held that P=I* E where P was watts. Maybe you would like to meet in the middle and use joule. I don't care. Power is power. energy is energy. measured in volume, rate, or potential is the difference.
Vlad Jovanovic said:Glenn, The standard unit for the rate of heat transferred, is in fact the WATT. So no reason to complicate things by converting to BTU's...Unless you Americans are dead set on it
Glenn said:Wattage is a measure we can use as an input into our Aquaponic system/structure. BTU is a measure of heat energy. And 1 watt-hour is equal to 3.413 BTU. No mattter how a watt of electrical energy is used within a structure or system,1 watt-hour is equal to 3.413 BTU.
Knowing the total size in area and volume, and total wattage used, one can calculate how much temperature rise or fall may be experienced.
You may also note that Each Horse Power used = 746 Watts
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