Air conditioners aren't cutting it

J232 said:

What’s the outside ambient and humidity like? That will play a role in the mini splits abilities too. I mean where the condenser is sitting, not necessarily outside.

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Aheadatime said:

30's outside, up to the 40's in the middle of the day. The units are rated for 5 degrees though, and I've ran other Friedrich units before in the winter down to 5-10 degrees. They're known for being able to work well in low temps.

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Aheadatime said:

I've got (2x) 22,000 BTU Friedrich mini split heat pumps installed for a 10k watt room. This room is in a basement, so it's got the natural cooling advantage. Insulated walls and ceiling. Ballast outside of room. Single ended bulbs. Plenty of airflow (and I mean plenty). With dehumidifiers and co2 burners off, and all 10 lights at 1,000w mode, the room is just about 90. That seems extremely high for me. Edit - This is canopy temp. The room temp is 85.


3,400 BTU per bulb without the ballast has always worked for me. That'd be 34,000 BTU, and I've got 44,000 BTU. Again, this is without dehues and burners. Just lights and fans. They've been installed and working for 4 weeks now, so if they had a refrigerant leak I think by now they'd be putting out warm air, but the air coming out of them feels cold. Could it be that the HVAC guy didn't charge enough refrigerant in the lines in the first place, lowering their efficiency? The ACs are set to Cool mode, fan speed is Auto, temp is 61 (the lowest you can set it).

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Aheadatime said:

I've got (2x) 22,000 BTU Friedrich mini split heat pumps installed for a 10k watt room. This room is in a basement, so it's got the natural cooling advantage. Insulated walls and ceiling. Ballast outside of room. Single ended bulbs. Plenty of airflow (and I mean plenty). With dehumidifiers and co2 burners off, and all 10 lights at 1,000w mode, the room is just about 90. That seems extremely high for me. Edit - This is canopy temp. The room temp is 85.


3,400 BTU per bulb without the ballast has always worked for me. That'd be 34,000 BTU, and I've got 44,000 BTU. Again, this is without dehues and burners. Just lights and fans. They've been installed and working for 4 weeks now, so if they had a refrigerant leak I think by now they'd be putting out warm air, but the air coming out of them feels cold. Could it be that the HVAC guy didn't charge enough refrigerant in the lines in the first place, lowering their efficiency? The ACs are set to Cool mode, fan speed is Auto, temp is 61 (the lowest you can set it).

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Kdoggy said:

Im a refrigeration mechanic by trade. Whats your temp in vs temp out on the head unit. Should be 20f. How long a lineset did he run. Units come charged with 15’ of lineset of charge anything extra distance from condenser to headunit is 5’ you need 3 ounces.

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Apalchen said:

I use double ended fixtures but I've always heard 6000 btu for de fixtures when you factor in heat load of the space and dehuey for that size area. I've always heard 5000 btu for single ended and 4000 btu for air cooled single ended.

I'd say your about 6000 btu short especially factoring in the burner and dehuey. I can't light my while room atm either because of lack of cooling and I know it sucks but you might have to shut off a light or two. Depending on your ballast you could possibly dim a couple lights and see if that works.

If you do think you have enough cooling though because you should be close, maybe try positions some extra fans move em around the room and try different places (try some up high and down low), I know it sounds crazy but I'm almost always pushing the limits with the amount of light I can cool and sometimes it is possible to lower the room and canopy temp quite a bit if you find the right placement for fans. Also try turning your mini split fan to high, you want as much air movement as possible in your room. I've had good luck with placing fans up high trying to create a vortex effect in the room.

Edit: sorry I just reread and saw you said you had a lot of air flow.

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cashflo718 said:

switch to LEDS and it'll fix alot of problems

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Aheadatime said:

The linesets were probably 20-30ft, and he did add refrigerant, but I got bad vibes from the guy since he made a mess of things and seemed new at the trade. I've heard it's difficult, but is it possible for a good HVAC guy to come take all the refrigerant out of the lines, weigh it to make sure there's the right amount, and add it back? Or would there be obvious symptoms that would give it away without having to do all of that, like noises or something?


I'll check those temps and let you know. Just putting a thermometer next to the intake and one next to the blower fan will do it?

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Aheadatime said:

but is it possible for a good HVAC guy to come take all the refrigerant out of the lines, weigh it to make sure there's the right amount, and add it back?

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Calculating Heat Load from Lighting Fixtures
Whenever doing heat-load calculations, we must always count 100% of the fixture wattage-any fixture's wattage-as heat, regardless of efficiencies at the source. In any enclosed space, virtually all of the light produced by a lighting fixture is eventually absorbed by surrounding materials (walls, ceilings, etc.). When light gets absorbed by these materials, photons are converted into heat.

New lighting technologies, such as LEDs, allow luminaires to produce light more efficiently, or with higher efficacy than incandescent lamps. This means that we get more lumens per watt; however, heat per watt is constant. What matters is that fewer watts are used to produce comparable brightness, not that these fixtures somehow produce less heat for the wattage that they consume.

1 watt of electricity used by a luminaire = 3.412 BTUs per hour

The same math works for any lighting fixture.

For average industrial heat-pump or electric air-conditioner types of HVAC equipment, it takes approximately 0.4 watts of cooling power to offset each 1 watt of power consumed by a light source. Smaller-scale HVAC systems might require more power than this, and certain specialized systems (such as evaporative coolers) may use somewhat less, but this is a useful generalization for most applications.

Occasionally users have commented, "I work in a cold climate, and the tungsten light fixtures provide heating to my space. If I change over to more energy-efficient lighting, I'll then have to use the HVAC system for heat, which would cancel out any energy savings." It is true that in cold environments some additional heating may be required due to the lower heat output of LEDs, but there will still be overall savings in the system. Industrial heating equipment utilizes energy sources like natural gas that are much less expensive for producing heat than electricity. In addition, it is much better at sending heat only where it's needed, rather than letting it pool unused in ceilings.

Some people include Carbon Footprint savings on an ROI spreadsheet, because it can help sell the green aspect of energy-efficient lighting. This varies by region, but an average calculation for many U.S. locations is 1.5 pounds (o.68kg) of CO2 per kilowatt-hour of electricity.

1 watt at luminaire = 3.412 BTUs per hour

1 watt at luminaire = 0.4 watts of air conditioning

1 watt at luminaire = 0.0015 pounds (0.00068kg) of CO2 per hour

so...

a 575 HPL * 3.412 = 1961.9 BTU's per hour

and...

a 750 HPL * 3.412 = 2559 BTU's per hour
.

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Renfro said:

Infrared is why HPS lights seem to run hotter than just the BTU's per watt. So when doing the math just based on how many watts are consumed you typically come up short with HPS lighting. With CMH it's not as bad (the amount of IR) and LED it's nearly non-existent.

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Kdoggy said:

Well i listen sometimes to the suction line on split system but a ductless split the metering device is in the condenser. Its ok if he was new but did he do it right is more the question. We can figure out whats wrong but you need a thermometer and honestly some effort. If your not up for that call the company who installed it and get them to figure out.

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Renfro said:

I find that with 10kW of HPS my 48,000 btu/hr (4 ton) unit is pushed to it's limits, basement here also with two 10kW rooms on a flip each with a 4 ton mini. You are right at 44,000 btu/hr so I wouldn't expect it to cool 10kW.

This is the correct way to charge a minisplit, pump it down and weigh out the charge and then you can weigh in a full charge. When evacuating the unit you can put the reclamation cylinder on the scales and see how much charge you pull out.

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Kdoggy said:

Usually btu is btu for sizing ive never heard of infrared being taken in sizing considerstions lol. Square feet and number of windows comes into sizing for a house but this is a sealed insulated unit. if a light puts off 3400 btu’s you need to size for that plus 1/4 more which is exactly how it was sized according to op.

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Aheadatime said:

Yeah I might have to have the units replaced with 36k units, for 72k btu total. They use the same lineset sizes, same 14aw too, would just need to upgrade the breaker. But that's also an expensive fix. Your 48k is from a central unit, or multiple splits?

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Aheadatime said:

Your 48k is from a central unit, or multiple splits?

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Kdoggy said:

Usually btu is btu for sizing ive never heard of infrared being taken in sizing considerstions lol.

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