Ph.D. in Chemistry, École Polytechnique
Dec 16, 2022
Residential photo voltaic panels can run any family utility, from mini audio system to a big warmth pump.
The latter has gained reputation in current occasions, with many owners in search of various family heating strategies within the type of geothermal or air-source warmth pumps.
On this article, we take a better have a look at warmth pumps, their vitality utilization, and the variety of panels you might want to energy one.
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Can photo voltaic panels run a warmth pump?
Warmth pumps and photo voltaic panels — two sustainable options for house consolation and energy era.
The latter type a part of modular photovoltaic (PV) programs, starting from a couple of watts to 1000’s of kilowatts.
Naturally, a industrial photo voltaic system with an influence output ranging within the 1000’s can simply energy a single warmth pump, however that’s not what we’re discussing right here.
You need to know whether or not a residential photo voltaic array can energy a warmth pump. Certainly, photo voltaic panels can run a warmth pump, even probably the most highly effective ones in the marketplace. What determines this, although, is the dimensions and variety of panels you could have obtainable to you.
Now, let’s have a look at this in larger element by reviewing how a warmth pump works and the way a photo voltaic panel produces electrical energy.
What’s a warmth pump?
Warmth pumps are the way forward for HVAC programs (Heating, Air flow, Air Conditioning). They’re reversible programs that may cool or warmth your house.
A warmth pump is just a warmth exchanger between the inside of your home and the air exterior. It really works like a fridge, with a compressor and a cooling/heating fluid.
Supply: College of Waikato
Warmth pumps are extra environment friendly than conventional air-con items as they don’t generate warmth. As an alternative, they “transfer” warmth by way of their exchanger system.
That mentioned, they nonetheless require electrical energy (800W to five,000W) to chill or warmth a house correctly.
What’s a photo voltaic panel?
A photo voltaic panel is an influence generator that converts daylight into electrical energy. You’ll discover photo voltaic panels starting from 20W as much as 600W.
You may join every unit to create a photo voltaic system with a a lot bigger energy output — the typical dimension within the U.S. is 6kW.
Nevertheless, a photo voltaic panel’s precise energy output hardly ever reaches its most rated worth. It varies in response to the time of day and the seasons in real-world situations.
For a 6kW photo voltaic system in San Francisco, California, the ability output reaches a most of 4kW–5kW (10 am–2 pm).
Supply: World photo voltaic atlas
What number of watts does a warmth pump use?
Should you’re contemplating shopping for a warmth pump, be ready to search out little or no data on its energy necessities.
Fortunate for you, we’re about to give you the components for calculating the variety of watts a warmth pump makes use of primarily based on its dimension and vitality effectivity.
The ability consumption —in watts — of a warmth pump relies on two main elements:
- Warmth pump dimension: This capability is rated in British Thermal Models (BTU). It varies from 8,000 BTU for the smallest fashions to greater than 60,000 BTU for centralized items.
- Power effectivity: In your warmth pump label, you’ll discover two figures:
- Seasonal Power Effectivity Score (SEER).
- Power Effectivity Score (EER).
The upper these numbers are, the extra environment friendly your warmth pump and the decrease its electrical energy consumption.
Calculating the variety of watts a warmth pump makes use of
To calculate a warmth pump’s wattage, you’ll want its heating capability — in BTUs — and its SEER and EER rankings.
If the EER ranking is indicated in your warmth pump label, then comply with the equation beneath:
Whole Wattage = Capability (In BTUs) ÷ EER
Should you solely have the SEER ranking, then you definately’ll want the next further calculation step to extract the EER ranking:
EER = −0.02 × SEER² + 1.12 × SEER
For instance, Comfortmaker’s Coastal warmth pump has a cooling capability of 28,000Btus (2.4 tons), SEER of 15 and EER of 12.5.
Its energy consumption is: 28,000/12.5= 2,240W
The identical cooling capability with a barely much less environment friendly unit (EER of 11) would end in an influence consumption of 2,545W. That’s a 13% improve that can straight affect your electrical energy invoice.
Desk
We utilized our components for various warmth pump capacities with effectivity rankings starting from 16–22:
| Warmth pump capability | Energy @16 SEER | Energy @18 SEER | Energy @20 SEER | Energy @22 SEER |
| 1 ton (12,000 BTU) | 938W | 877W | 833W | 802W |
| 1.5 ton (18,000 BTU) | 1,406W | 1,316W | 1,250W | 1,203W |
| 2 ton (24,000 BTU) | 1,875W | 1,754W | 1,667W | 1,604W |
| 2.5 ton (30,000 BTU) | 2,344W | 2,193W | 2,083W | 2,005W |
| 3 ton (36,000 BTU) | 2,813W | 2,632W | 2,500W | 2,406W |
| 3.5 ton (42,000 BTU) | 3,281W | 3,070W | 2,917W | 2,807W |
| 4 ton (48,000 BTU) | 3,750W | 3,509W | 3,333W | 3,209W |
| 4.5 ton (54,000 BTU) | 4,219W | 3,947W | 3,750W | 3,610W |
| 5 ton (60,000 BTU) | 4,688W | 4,386W | 4,167W | 4,011W |
What number of photo voltaic panels do you might want to run a warmth pump?
The smallest warmth pump solely requires three x 500W photo voltaic panels to run accurately. Bigger centralized items would wish a whole 6,000W photo voltaic system 6,000W (12 x 500W panels) as a minimal requirement.
To calculate the variety of photo voltaic panels you might want to run a warmth pump, you’ll have to assemble the next data:
- Your local weather zone.
- The dimensions of the house you need to warmth.
- Your photo voltaic electrical energy manufacturing potential
Supply: 2012 IECC – Worldwide Power Conservation Code
| Local weather Zone | BTU/Sq.Ft |
|---|---|
| Zone 1 | 30 BTU/sq.ft |
| Zone 2 | 35 BTU/sq.ft |
| Zone 3 | 40 BTU/sq.ft |
| Zone 4 | 45 BTU/sq.ft |
| Zone 5 | 50 BTU/sq.ft |
| Zone 6 | 55 BTU/sq.ft |
| Zone 7 | 60 BTU/sq.ft |
Instance
San Francisco, California, falls beneath local weather Zone 3. You’ll want a heating capability of 40 BTU/sqft. For a 1000 sqft home, you’ll want a warmth pump with a heating capability of 40,000 BTU/h.
A 40,000 BTU/h warmth pump with an effectivity ranking of 20 (SEER) can have roughly 3kW of energy.
This warmth pump will solely run at full energy among the time. Let’s say it’ll run round 6 hours every day, relying on the surface temperature.
On this state of affairs, it’ll use roughly 18kWh per day to warmth your home throughout winter in San Francisco.
Calculate your photo voltaic vitality potential
We suggest utilizing our photo voltaic calculator to estimate your photo voltaic electrical energy manufacturing potential. You’ll solely want your deal with and the dimensions of your photo voltaic system.
You may apply the components beneath:
Variety of photo voltaic panels = Every day warmth pump vitality wants / photo voltaic vitality manufacturing potential
Throughout San Francisco’s winter months, you’ll be able to anticipate to provide 3.45kWh per day for each kW of photo voltaic panels. Consequently, to cowl your warmth pump’s electrical energy wants, you’ll want 5.2kW of photo voltaic panels — 18 / 3.45 = 5.2kW.
That’s equal to 11 x 500W photo voltaic panels (5.5kW).
Word to our readers: All figures are common values. A number of exterior elements can affect the vitality consumption of your warmth pump —exterior temperature, home thermostat temperature, and so forth.
Last ideas
Heating and cooling account for round 65% of all home vitality use within the U.S. Extra particularly, house heating is near 30%.
A warmth pump is considered probably the most environment friendly HVAC know-how. It could minimize your vitality invoice by an element of two–3.
Warmth pumps are highly effective home equipment, starting from 800W to greater than 5,000W, however like most home home equipment, you’ll be able to energy with photo voltaic panels so long as you could have the suitable quantity obtainable.
As a rule of thumb, a warmth pump wants between 3–12 500W photo voltaic panels.
Lastly, keep in mind that warmth pump vitality use relies on exterior elements reminiscent of exterior temperature, home temperature, and time of the 12 months.
