Real handy water electrical heating calculators.

[Mattb4]

This site has some handy heating calculators. https://bloglocation.com/art/water-heating-calculator-for-time-energy-power

I stumbled upon it yesterday after spending half my day plumbing in a new hot water tank. (did a major redo of the pipes from the pump , filter and new tank placement location)This tank is a Rheem 30gal. tank that came with 2-4500w elements wired for 240v. I removed the factory elements and replaced them with 120v, 2000w elements instead so that I could use it with my solar power system via an individual transfer switch. One thing I was curious about was just how much time it would take to heat the water up to 135F from the base temperature of around 65F.

Using the calculator for time to heat up the numbers were 30gal., 65F, 2000w and the results were 2h-35m. My measured time from energizing the tank to temperature shutoff came in at 2h-40m being powered from the grid. The approximate power used was 5.3Kwh. The calculator on the site for the same numbers comes in at 5.14Kwh Considering my present solar arrays values of 2000w it would be unlikely to that I would be using it as a every day situation. I expect I mostly will continue to use grid but I now can supplement water heating on those days when my batteries get fully charged by noon.

 

[SeaGal]

Thanks for that... am working on an immersion heater diverter project at the moment, so that will come in handy... it even handles our proper-sized gallons compared to your small ones

 

[lucariffer]

I note that Deye (Chinese supplier to EG4, including EG4's new ACDC HVAC unit) also makes a PV-powered ACDC water tank heater (link https://www.deyeinverter.com/product/solar-air-conditioner/hybrid-acdc-solar-air-water-heater.html) It would be nice if EG4 imported that product too.

 

[Mattb4]

Thanks for that... am working on an immersion heater diverter project at the moment, so that will come in handy... it even handles our proper-sized gallons compared to your small ones

I thought you folks were metric? But the calculator seems to cover most of the standards except the Chinese whose measurements is depending on the cycle of the moon and thumb on scale.

 

[Mattb4]

I note that Deye (Chinese supplier to EG4, including EG4's new ACDC HVAC unit) also makes a PV-powered ACDC water tank heater (link https://www.deyeinverter.com/product/solar-air-conditioner/hybrid-acdc-solar-air-water-heater.html) It would be nice if EG4 imported that product too.

A combo solar powered A/C unit with water heating as a by product has a lot of merit. But I bet it don't come cheap.

 

[SeaGal]

I thought you folks were metric? ...

LOL... we're weird over here... we measure road distances in miles, buy fuel in litres, but measure car consumption in miles-per-gallon (English gallons of course!). And us oldies still think about feet and inches!

Then.. in theory, we buy food in grams and litres... but in practice most items are sold in contains relating to their old measurements (yep 50 years later)... So we can buy milk in containers of either 568ml or 1.136litres = 1 or 2 pints... proper English pints that is, not American ones. And jam in jars of 454g = 1 pound (at least we agree on that one!).

Don't get me starting on car tyres (= tires)... they are sold with measurements like 245/35x19. Where the 245 is the width of the tread in millimetres, 35 is the sidewall measurement as a percentage of the width (so 35% of 245mm). And yes, you guessed it, the 19 is the diameter of the wheel..... in inches!