i like that guys duct layout... spiral steel duct is the shit.
i dont like those registers though. drum louvers are better as they give you far better control of the direction.
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Central Air: 2 x 3 Tons or 6 Tons?
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i like that guys duct layout... spiral steel duct is the shit.
i dont like those registers though. drum louvers are better as they give you far better control of the direction.
i was looking for a old thread, but as always when you are looking for something..
anyway the guy in that thread was using
WATER-COOLED HEAT EXCHANGERS for a similar size setup...
they pull less power and are very efficiant, but you would need something to control humidity then, so maybe run a hybrid setup
with AC & Heat Exchanger
i always find the problem with running AC´s is the power they draw..
but queequeq knows his stuff...
i have not set up a room this big, but from experience its always better having two units in case one fails, like already mentioned.. so you can at least run some lights till things are fixed. Also split systems dont leak smell like already mentioned, very important.. but you got that figured..
id honestly look into the water cooled heat exchangers, as in the end you dont want to run half the power of your room just for cooling, not forgetting the massive electricity bill that will arouse suspicion
check these people out, they also have the yorks you were looking into and the heat exchangers:
http://www.heatexchanger.ca/cooling-blowing
anyway the guy in that thread was using
WATER-COOLED HEAT EXCHANGERS for a similar size setup...
they pull less power and are very efficiant, but you would need something to control humidity then, so maybe run a hybrid setup
with AC & Heat Exchanger
i always find the problem with running AC´s is the power they draw..
but queequeq knows his stuff...
i have not set up a room this big, but from experience its always better having two units in case one fails, like already mentioned.. so you can at least run some lights till things are fixed. Also split systems dont leak smell like already mentioned, very important.. but you got that figured..
id honestly look into the water cooled heat exchangers, as in the end you dont want to run half the power of your room just for cooling, not forgetting the massive electricity bill that will arouse suspicion
check these people out, they also have the yorks you were looking into and the heat exchangers:
http://www.heatexchanger.ca/cooling-blowing
i like chillers alot.... no trunk and branch, just a 2" water line heading off to some fan coils.
they are alot more flexible and require far less ducting.... however they are only marginally more efficient, and ONLY when using low velocity low power air handlers... if you want agressive air exchanges and good filtration you will need a powerful blower like what you find in forced air systems.
media air filters and what ever treatment systems you desire require these blowers.
chillers CAN DEHUMIDIFY just fine... you just have to engineer the thing properly. if your chill water is like 60 degrees by the time it reaches your fan coil, you failed at hvac.
the biggest problem with chillers is they simply do not make them cheap enough for folks to even consider them for residential construction.
there is simply nobody interested in installing them into homes, so the big companies just dont build them.
to my knowledge, you cannot buy a 5 ton chiller for anywhere near the cost of a 5 con condensing unit
edit:
let me clarify something... WATER cooled chillers can be much more efficient... (cop well over 4... ) but im talking about air cooled chillers.
they are alot more flexible and require far less ducting.... however they are only marginally more efficient, and ONLY when using low velocity low power air handlers... if you want agressive air exchanges and good filtration you will need a powerful blower like what you find in forced air systems.
media air filters and what ever treatment systems you desire require these blowers.
chillers CAN DEHUMIDIFY just fine... you just have to engineer the thing properly. if your chill water is like 60 degrees by the time it reaches your fan coil, you failed at hvac.
the biggest problem with chillers is they simply do not make them cheap enough for folks to even consider them for residential construction.
there is simply nobody interested in installing them into homes, so the big companies just dont build them.
to my knowledge, you cannot buy a 5 ton chiller for anywhere near the cost of a 5 con condensing unit
edit:
let me clarify something... WATER cooled chillers can be much more efficient... (cop well over 4... ) but im talking about air cooled chillers.
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could be a option to find a industrial 2nd hand unit? insolvency or something.. theres enough units out there A LOT cheaper i bet.. also a lot easier to repair and less components then AC??
components that can break in the long run i mean..
just thoughts
components that can break in the long run i mean..
just thoughts
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I would go with a chiller system. If you really want an air to air system look into the inverter condensing units and variable speed air handlers. They will give you the best humidity control and control compressor speed based on the heat load.
Make sure your HVAC guy sizes the duct work properly and uses proper diffusers.
Make sure your HVAC guy sizes the duct work properly and uses proper diffusers.
an industrial chiller will be far and away larger than necessary.
there are niche companies building chillers from OEM equipment... have been for years, but these units cost a fortune, and are usually billed as alternatives to super high velocity AC systems in old house restorations and shit like that.
you COULD buy a bunch of ground source heat pumps and run them on tap water... but we would be talking about lots of wasted water here. idk where this gentleman lives, but water in california is.... you know.
there are niche companies building chillers from OEM equipment... have been for years, but these units cost a fortune, and are usually billed as alternatives to super high velocity AC systems in old house restorations and shit like that.
you COULD buy a bunch of ground source heat pumps and run them on tap water... but we would be talking about lots of wasted water here. idk where this gentleman lives, but water in california is.... you know.
Now it makes more sense! I was adding stage 1 and stage 2. Didn't realize I wasn't supposed to. You really know your shit!
2003 York YCAL 14 ton Air Cooled Chiller 208/220V TESTED, Dual Scrolls Low Amb.
30Amps - $9,400.00
http://www.ebay.com/itm/2003-York-Y...4&pid=100005&rk=2&rkt=6&sd=171466125473&rt=nc
30Amps - $9,400.00
http://www.ebay.com/itm/2003-York-Y...4&pid=100005&rk=2&rkt=6&sd=171466125473&rt=nc
lol what do you think the freight cost for that would be?
i honestly dont know but im betting its like at least a couple bucks a mile...
also, this is a three phase unit obiviously... does the OP even have 3 phase power?
lol, its just such a bad idea, but i admit... it would be badass to fuck with a giant skid chiller.
i honestly dont know but im betting its like at least a couple bucks a mile...
also, this is a three phase unit obiviously... does the OP even have 3 phase power?
lol, its just such a bad idea, but i admit... it would be badass to fuck with a giant skid chiller.
If you need it to run at very low outside temps I reccomend a unit with a heat pump. Adding a heat pump to your unit allows the gases to reverse so that it will auto defrost. You would never use the heat pump to produce heat bc electrical heat is very expensive but it allows your AC to have a low ambient kit.
Ps Billboat is the man I would take his Advice. He has been killing it big rooms alone for some time now on the farm and now here check out his threads of you haven't alteady. He has one of the biggest workloads that I see posted now a days online
Ps Billboat is the man I would take his Advice. He has been killing it big rooms alone for some time now on the farm and now here check out his threads of you haven't alteady. He has one of the biggest workloads that I see posted now a days online
hm. heat pumps freeze because they are using the condensing coil as an evaporator...
you should not be freezing your out door unit by running it in a cooling mode... a cold start kit simply allows the unit to operate such that the refrigerant boiling inside your evaporator does not get so cold that it freezes your evaporator coil assembly.
with that said, you might actually want a heat pump model... being that when your lighting system is not in use this room will cool off quite quickly in such low temps.
cold start equipment varies across all of the manufacturers... you must consult your particular manufacturers equipment documents to find out what parts you need to order with your unit.
most modern ac systems are easily able to handle these cold start kits and might even have knockouts and screw holes drilled ready accept the additional wiring and parts.
to retrofit one of these kits into an older job, you pretty much just need to add some sensors to the condensing unit and wire in a relay module that slows down the fan speed such that you get an appropriate super cool.
if the condensing unit fan is shitty and old, you would probably just replace the fan motor and caps while you are at it... these things do tend to fail, and a new psc condenser fan motor is like 80 bucks new, caps another 10 bucks maby.
newer jobs can have ecm variable speed motors that automatically drop to quieter and more efficient speeds when the unit is running in a low stage or when the ambients are low. my understanding is these units do not require fan speed intervention for cold starting... they can handle that on their own. whether or not they have the sensors is another thing... but they are trivial to retrofit in. you just need a little thermistor or a little bimetal thermostat button on the inside of the condensor coil, and another on the vapor return line coming off of your evaporator close to the txv bulb.
the condenser sensor alert to cold conditions wherein a slower fan speed is required.
the evaporator sensors alert to flooding conditions in the event that your TXV fails to do its job(rare), or if you just dont have a TXV.
flooding occurs when coils freeze or systems are overcharged such that liquid refrigerant passes through the vapor return lines and get sucked into a compressor.
hvac compressors can not compress incompressible things such as fully liquified refrigerants just as car engines cannot compress incompressible liquids like water without failing catastrophically.
there are however a number of features present in most ac systems that prevent this from occuring... even with poorly maintained or over charged systems.
you should not be freezing your out door unit by running it in a cooling mode... a cold start kit simply allows the unit to operate such that the refrigerant boiling inside your evaporator does not get so cold that it freezes your evaporator coil assembly.
with that said, you might actually want a heat pump model... being that when your lighting system is not in use this room will cool off quite quickly in such low temps.
cold start equipment varies across all of the manufacturers... you must consult your particular manufacturers equipment documents to find out what parts you need to order with your unit.
most modern ac systems are easily able to handle these cold start kits and might even have knockouts and screw holes drilled ready accept the additional wiring and parts.
to retrofit one of these kits into an older job, you pretty much just need to add some sensors to the condensing unit and wire in a relay module that slows down the fan speed such that you get an appropriate super cool.
if the condensing unit fan is shitty and old, you would probably just replace the fan motor and caps while you are at it... these things do tend to fail, and a new psc condenser fan motor is like 80 bucks new, caps another 10 bucks maby.
newer jobs can have ecm variable speed motors that automatically drop to quieter and more efficient speeds when the unit is running in a low stage or when the ambients are low. my understanding is these units do not require fan speed intervention for cold starting... they can handle that on their own. whether or not they have the sensors is another thing... but they are trivial to retrofit in. you just need a little thermistor or a little bimetal thermostat button on the inside of the condensor coil, and another on the vapor return line coming off of your evaporator close to the txv bulb.
the condenser sensor alert to cold conditions wherein a slower fan speed is required.
the evaporator sensors alert to flooding conditions in the event that your TXV fails to do its job(rare), or if you just dont have a TXV.
flooding occurs when coils freeze or systems are overcharged such that liquid refrigerant passes through the vapor return lines and get sucked into a compressor.
hvac compressors can not compress incompressible things such as fully liquified refrigerants just as car engines cannot compress incompressible liquids like water without failing catastrophically.
there are however a number of features present in most ac systems that prevent this from occuring... even with poorly maintained or over charged systems.
Low Ambient Cooling
https://yorkcentraltechtalk.wordpress.com/2013/05/03/low-ambient-cooling/
"As you can see, this manufacturer does not recommend running the unit below 50*F unless a low ambient kit is installed on the unit. So, this is what the basis of this posting will be about — low ambient cooling when you are below the manufacturers published Application Limitations. This can vary depenting on the type of unit or manufacturer so you need to check out what the manufacturer’s limitations are for the specific equipment you are working on.
On light commercial (non-process cooling) applications, one solution would be to install an Economizer on a packaged roof top unit. This would allow cool outside air to be used to cool the space below 50 degrees. The compressors or mechanical cooling could be “locked out” through a thermostat or “klixon” type switch so it cannot run below a pre-set temperature. Economizers on packaged equipment are a great and “economical” way to provide cooling below the applicaion limitiations of the equipment.
If mechanical cooling is needed and the economizer could not keep up or the application of an econoimizer could not be used due to the type of equipment or location, the next suggestion would be to add some sort of low ambient “fan cycling” control to the unit to maintain head pressure/suction pressure. Again, on light commercial (non-process cooling applications) or the occasional residential customer who wants cooling any time they feel like it, this is probably the best suggestion.
There are a couple of types of controllers — the most basic and simplest is cycling the fan on a pressure switch. These are designed to regulate condenser liquid pressure at low outdoor ambient temperatures by controlling the airflow over the condenser. The low ambient pressure kit will energize the outdoor motor when the liquid line pressure reaches 300 +/-10 PSIG for R-22 models and 360 +/-10 PSIG for R-410A models. It will stop the motor when the pressure falls below 150 +/- PSIG for R-22 models and 240 +/- PSIG for R-410A models thus keeping the pressures high enough so the coil does not “freeze”. This type is fine for the occasional need for low ambient cooling. If the space is going to regularly need low ambient cooling, then a true fan cycler type control is the best way to go.
This type of control monitors the liquid line temperature (which of course corresponds to pressure) and then modulates the speed of the condenser fan(s) to maintain head pressure. The main caution with these are making sure you set it up for the correct type of motor — ball bearing or sleeve bearing — so you don’t start having motor failures. As the unit is running, there is a sensor (resistor) strapped to the liquid line and insulated and then, based on the temperature it is reading, allows the fan to speed up or slow down (or if too low — turn off the fan eventually) to maintain a very consistent head pressure. Most of these controls will work with both the ball bearing or sleeve bearing motors and allows you to select which one your application has.
This is a very “simple” description of low ambient cooling but, hopefully, you can see how important this is to proper operation of cooling equipment. One other very important thing to mention is, if you are going to do low ambient cooling on any piece of equipment, be sure it has a functioning crank case heater on the compressor. Without a functioning crank case heater, the oil in the compressor will absorb liquid refrigerant (since one of the principles of refrigerants is that they always migrate to the coldest spot and the compressor in winter/early spring is that spot) and when the unit tries to start, the liquid will begin to boil off and carry a lot of the oil out of the compressor which could lead to early compressor failure."
https://yorkcentraltechtalk.wordpress.com/2013/05/03/low-ambient-cooling/
"As you can see, this manufacturer does not recommend running the unit below 50*F unless a low ambient kit is installed on the unit. So, this is what the basis of this posting will be about — low ambient cooling when you are below the manufacturers published Application Limitations. This can vary depenting on the type of unit or manufacturer so you need to check out what the manufacturer’s limitations are for the specific equipment you are working on.
On light commercial (non-process cooling) applications, one solution would be to install an Economizer on a packaged roof top unit. This would allow cool outside air to be used to cool the space below 50 degrees. The compressors or mechanical cooling could be “locked out” through a thermostat or “klixon” type switch so it cannot run below a pre-set temperature. Economizers on packaged equipment are a great and “economical” way to provide cooling below the applicaion limitiations of the equipment.
If mechanical cooling is needed and the economizer could not keep up or the application of an econoimizer could not be used due to the type of equipment or location, the next suggestion would be to add some sort of low ambient “fan cycling” control to the unit to maintain head pressure/suction pressure. Again, on light commercial (non-process cooling applications) or the occasional residential customer who wants cooling any time they feel like it, this is probably the best suggestion.
There are a couple of types of controllers — the most basic and simplest is cycling the fan on a pressure switch. These are designed to regulate condenser liquid pressure at low outdoor ambient temperatures by controlling the airflow over the condenser. The low ambient pressure kit will energize the outdoor motor when the liquid line pressure reaches 300 +/-10 PSIG for R-22 models and 360 +/-10 PSIG for R-410A models. It will stop the motor when the pressure falls below 150 +/- PSIG for R-22 models and 240 +/- PSIG for R-410A models thus keeping the pressures high enough so the coil does not “freeze”. This type is fine for the occasional need for low ambient cooling. If the space is going to regularly need low ambient cooling, then a true fan cycler type control is the best way to go.
This type of control monitors the liquid line temperature (which of course corresponds to pressure) and then modulates the speed of the condenser fan(s) to maintain head pressure. The main caution with these are making sure you set it up for the correct type of motor — ball bearing or sleeve bearing — so you don’t start having motor failures. As the unit is running, there is a sensor (resistor) strapped to the liquid line and insulated and then, based on the temperature it is reading, allows the fan to speed up or slow down (or if too low — turn off the fan eventually) to maintain a very consistent head pressure. Most of these controls will work with both the ball bearing or sleeve bearing motors and allows you to select which one your application has.
This is a very “simple” description of low ambient cooling but, hopefully, you can see how important this is to proper operation of cooling equipment. One other very important thing to mention is, if you are going to do low ambient cooling on any piece of equipment, be sure it has a functioning crank case heater on the compressor. Without a functioning crank case heater, the oil in the compressor will absorb liquid refrigerant (since one of the principles of refrigerants is that they always migrate to the coldest spot and the compressor in winter/early spring is that spot) and when the unit tries to start, the liquid will begin to boil off and carry a lot of the oil out of the compressor which could lead to early compressor failure."
sure i was exaggerating with that ebay post, but just wanted to show, theres systems to be had for good money, what MIMedhaed said was also running through my head, a heat pump model.. so you got full control in winter & summer.. i have 2 units, work great!
another idea: split the room in 2.. not sure if the gavitas are remote, but you could run the lights on flip flops, so if room A is lights on, you warm room B with the exhaust from A.. vise versa, im sure you can get away with a lot smaller central, air cooling or what not unit, save maybe on power but for sure you save on material costs.
plus i think its easier controlling 2 smaller rooms than one massive room.. pests, climate, nutes whatnot
another idea: split the room in 2.. not sure if the gavitas are remote, but you could run the lights on flip flops, so if room A is lights on, you warm room B with the exhaust from A.. vise versa, im sure you can get away with a lot smaller central, air cooling or what not unit, save maybe on power but for sure you save on material costs.
plus i think its easier controlling 2 smaller rooms than one massive room.. pests, climate, nutes whatnot
I never use my heat pump on my AC that is very expensive heat. I use a forced air gas furnace for lights off temps. I mentioned adding a heat pump to the unit he is getting because that allows the AC that normally should not be ran at a temp of 45F and below and allows the unit to be run at 20F temps with out problems. My 4 ton split Ac has a heat tape wrapped around the the tank in the compressor outside aswell at the pressure switch that shuts off the system when the pressure builds up to 300psi. I should have bought a unit with a heat pump it's basically a built in low ambient kit for your AC just like mini splits that have them and can run down to 15F. Saying that I would never use the heat pump on my AC to create heat bc electric heat is stupid expensive.
I own a 3 ton mini split with heat pump for a different for room
My main 12kw room is heated and cooled with
4 ton split AC with heat tape
Furnace blower sized to go with the 4 ton AC
My favortie piece of hvac equipment is my Sensi smart thermostat. I can see temps and humidity from my phone 24hrs a day I can also adjust the temps to what ever I want whenever I want. Right now I have it set to auto mode which is two set points if it goes above 82F my AC kicks on, and if it goes below 73f my furnace turns on. Basically the AC only runs lights on and furnace only runs lights out when the temps drop.
I own a 3 ton mini split with heat pump for a different for room
My main 12kw room is heated and cooled with
4 ton split AC with heat tape
Furnace blower sized to go with the 4 ton AC
My favortie piece of hvac equipment is my Sensi smart thermostat. I can see temps and humidity from my phone 24hrs a day I can also adjust the temps to what ever I want whenever I want. Right now I have it set to auto mode which is two set points if it goes above 82F my AC kicks on, and if it goes below 73f my furnace turns on. Basically the AC only runs lights on and furnace only runs lights out when the temps drop.
i think you are confusing heat pumps with electric resistance heating.
heat pumps are much more efficient than the latter. in mild climates its hard to justify the expense and hassle of installing a gas furnace unless you already have gas service and gas appliances.
a heat pump does cost more than gas to run kw to kw, however in climates that are mild, like mine, you have so few heating days... that it takes like 10 years in some cases to pay for the cost of a 90+% efficient furnace. far more time if you need to pay to plumb gas lines and trench your yard up for a service connection.
in places like NY where gas prices are comparitivly low and electricity costs are very high... gas furnaces are necessary. in places like houston, where electricity and gas are low cost, its not worth the additional cost unless you already have it.
i think it costs something like 7 bucks a month just to have gas service connected to your home+ some small taxes and fees.
regarding splitting the lighting load into two cycles... yes you could reduce your equipment size to roughly half. however this equipment would run twice as long so you are essentially running the same amount of KWh through your meter.
this split setup would require a legit zoneing system also... so add probably 500-700 bucks to your duct construction bill of materials.
heat pumps are much more efficient than the latter. in mild climates its hard to justify the expense and hassle of installing a gas furnace unless you already have gas service and gas appliances.
a heat pump does cost more than gas to run kw to kw, however in climates that are mild, like mine, you have so few heating days... that it takes like 10 years in some cases to pay for the cost of a 90+% efficient furnace. far more time if you need to pay to plumb gas lines and trench your yard up for a service connection.
in places like NY where gas prices are comparitivly low and electricity costs are very high... gas furnaces are necessary. in places like houston, where electricity and gas are low cost, its not worth the additional cost unless you already have it.
i think it costs something like 7 bucks a month just to have gas service connected to your home+ some small taxes and fees.
regarding splitting the lighting load into two cycles... yes you could reduce your equipment size to roughly half. however this equipment would run twice as long so you are essentially running the same amount of KWh through your meter.
this split setup would require a legit zoneing system also... so add probably 500-700 bucks to your duct construction bill of materials.
because night time transpiration is almost without exception, a small fraction of what it is during the daytime.
dem stomata close tight yo.
dem stomata close tight yo.
Great information here! I realize that a couple dehumidifiers aren't going to give me the heat that I need on winter nights. This is all taken into account. I won't be using Heat Pumps. I'll be running Gas Heating Systems. Most likely forced hot water. I really like how this thread has developed.
