Solar Electric to Hot Water the Easy Way, a Solar Hybrid System

[techluck]

I know the water heater takes a lot of daily power so I looked into choices of going solar. I priced a system that had a lot of plumbing and it's way too much $$$. I really don't want to mess with the house plumbing, actually I don't want to change much at all.

So I thought it would be great if there was a way to use regular PV solar panels that I could also re-configure in an emergency to give me power. If it could "assist" the water heater that would be fine since it has a daily heat loss even if I don't use it.

Now I have the upper electric element hooked to the grid and the lower element connected through a MPPT controller which keeps the upper element from coming on all that much. It's now a hybrid. It isn't a total replacement for the grid, but it really reduces the grid usage. And I can always switch back whenever I want because I only disconnected the two lower wires and can connect them back at any time.

The wattage it puts in as heat adds up all day long, like a storage battery.

I thought maybe other people would be interested in this simple solution too.

[nilvenjhon]

Well, the solar hybrid system is very useful these days and there are numbers of people using these system for their home especially. Although, it designed with great flexibility which helping people to add as many solar panels.

[russ]

Well, the solar hybrid system is very useful these days and there are numbers of people using these system for their home especially. Although, it designed with great flexibility which helping people to add as many solar panels.

Horribly inefficient and a total waste!

[techluck]

Horribly inefficient and a total waste!

At first I thought that too, but the government did a study years ago and said that once panels got below $1.50/W that it would be cost effective. Some panels are going for 75c/W in qty one right now.

http://fire.nist.gov/bfrlpubs/build02/PDF/b02012.pdf

Their system wasn't all that simple either.

With MPPT the power coming from the panels goes directly to the water with only a small wire loss (voltage near 60V most of the time) and a small loss through the controller (a few watts). The energy adds up all day long and is stored in the tank.

[russ]

At first I thought that too, but the government did a study years ago and said that once panels got below $1.50/W that it would be cost effective. Some panels are going for 75c/W in qty one right now.

It is horribly inefficient - a solar thermal panel (quality) will be at least 50% efficient and possibly much higher - a solar PV panel < 20% for sure.

If you want to go down the electric road look at the heat pump style water heaters - Today they are the most efficient over a 13 year cycle in a mild climate. If they are located in a heated space that is not true.

[techluck]

It is horribly inefficient - a solar thermal panel (quality) will be at least 50% efficient and possibly much higher - a solar PV panel < 20% for sure.

If you want to go down the electric road look at the heat pump style water heaters - Today they are the most efficient over a 13 year cycle in a mild climate. If they are located in a heated space that is not true.

It's not horrible, it's practical.

For people who don't want to invest $10,000 on a installed fluid based system and worry about leaks, freezing and pumps going out, this is a good choice.

It's going to be efficient in that if you put 440W in, you get 440W of heat to the water for hours and hours all day long which adds up and you don't have to pay for that from the power company. Easy and simple.

There are other factors, like I didn't want to do any plumbing or drain the tank or change anything that I couldn't easily put back. If I move I want to take my equipment with me.

Wires are so easy to install, run around corners and connect since it's only 2 wires + and -. It was a easy install and just a few hours.

I also want to have the panels available for an emergency as extra power. All I have to do is reconfigure them to 24V (parallel) and connect them to my batteries. My choice whether hot water or battery charging is important in whatever emergency situation happens.

Smart meters are another issue, the standard cheap one that they are doling out to everyone does not go "backwards" so a lot of people can't go with a GTI. This gets around the smart meter problem.

One guy contacted me and wants to put 2 of these, one on each element and 880W of panels so he can go totally off grid. He's willing to conserve of course, and schedule his usage but I think he's going to be happy for the low investment. 880W all day long is going to be a lot of total daily power.

On a fluid system there has to be piping heat loss, and 2nd tank heat loss that is going to impact a fluid based system anyway, so there are inefficiencies there too.

There are trade-offs for all this stuff, but I think this makes the most sense, money, time and trouble wise.

[inetdog]

Wires are so easy to install, run around corners and connect since it's only 2 wires + and -. It was a easy install and just a few hours.

One of the use cases featured on the site was an existing apartment complex where either running fluid to each unit or providing a common preheat source to existing per-unit water heaters was impractical. Not to mention maintenance problems. The returns are less than you would get from a comparable expenditure on solar thermal, but as techluck points out there are cases where the cost of solar thermal will be totally dominated by the installation cost. There was no "comparable expenditure" opportunity.

PS: Which leaves it to fly or fall on its own merit rather than by comparison to solar thermal.
A valid comparison would be to using the same panels to feed a GTI, except in those few areas that have neither net metering laws nor other incentives.
But be sure to add in the design and permitting cost when evaluating the GTI option. Running PV DC to a water heater would be much easier to get a permit for in most areas.

[Naptown]

So the truth comes out Techluck. You are selling this stuff. Nice try on the link in the signature line it will be removed.
If you would like to advertise your product please contact user Jason for advertising rates.
Reinsertion of the ad link will be cause for your being banned as a spammer.

[russ]

It's going to be efficient in that if you put 440W in, you get 440W of heat to the water for hours and hours all day long which adds up and you don't have to pay for that from the power company. Wow!

There are other factors, like I didn't want to do any plumbing or drain the tank or change anything that I couldn't easily put back. If I move I want to take my equipment with me. That is a load - picking up an moving a system though some might do it.

Wires are so easy to install, run around corners and connect since it's only 2 wires + and -. It was a easy install and just a few hours.

I also want to have the panels available for an emergency as extra power. All I have to do is reconfigure them to 24V (parallel) and connect them to my batteries. My choice whether hot water or battery charging is important in whatever emergency situation happens. Right - shade tree stuff 99% won't be interested in

Smart meters are another issue, the standard cheap one that they are doling out to everyone does not go "backwards" so a lot of people can't go with a GTI. This gets around the smart meter problem.Blowing smoke?

One guy contacted me and wants to put 2 of these, one on each element and 880W of panels so he can go totally off grid. He's willing to conserve of course, and schedule his usage but I think he's going to be happy for the low investment. 880W all day long is going to be a lot of total daily power.le of living - basically you are dreaming.Only for a very frugal styp

On a fluid system there has to be piping heat loss, and 2nd tank heat loss that is going to impact a fluid based system anyway, so there are inefficiencies there too. More smoke.

There are trade-offs for all this stuff, but I think this makes the most sense, money, time and trouble Think and do what you want as long as it is legal - for the 99% this is not at all attractive.

Comments in bold within the text.