Piggyback

Piggyback® is appropriately named because a traditional hot water heater is positioned on top of the 30”x30”x24”high Trendsetter® solar hot water “drain-back” tank.

This new tank has several key advantages over the two tank solar pre-heat system and will prove to be 13.5% more efficient and requiring no electricity to operate. It is designed to reduce the “burn time” of a water heater by 60%-75%.

• Saves space
• Transfers solar heat 24 hours a day by natural convection
• Uses no electrical power from the grid
• Passively optimizes solar storage capacity
• Minimizes maintenance with only one active component

Natural Gas Water Heaters

The system is anticipated to replace 2/3rds of the hot water demand of the household resulting in a savings of 182 therms per year. If a “therm” of natural gas costs $1.75 the first year savings at present natural gas rates would be $320. Assuming fuel costs will double in the next 5 years the net investment will be recouped in 7-9 years. The system cost will also be recouped a second time if you live in the house another 4 years.

Electric Water Heaters

An electric water heater will consume the equivalent of 4,275 KW-h to heat the 80 gallon per day for an entire year. The solar will save 2/3rds of this load or 2,851 KW-h. At a cost of .25/KW-h the first year’s savings will be $712. Using the assumption that electricity will double in 5 years the net investment will recoup in 5-7 years The system cost will also be recouped a second time if you live in the house another 3 years.

Natural Gas Water Heaters

The average family uses 60-80 gallons of hot water each day. A natural gas water heater which is typically 58% efficient generates 3,200 pounds of CO₂ emissions per year. Solar saves the average household 2/3rds of the fossil fuel energy consumed for water heating and save 2,131 pounds of CO₂ annually.

Electric Water Heaters

An electric water heater will consume 4,275 KW-h annually to heat the 80 gallon of hot water each day. The solar water heater saves at least 2,851 KW-h of this amount. Half of all power plants in the US use coal to generate electricity. By replacing electricity with solar to heat water, you will save 6,272 pounds of CO₂ annually.

By comparison the average family drives 12,497 miles per year. This generates 10,899 lbs of CO₂ annually. If you trade in your 20 mpg family car for a 35 mpg car you will also save 6,228 lbs of CO₂ annually.

The new evacuated tube solar collectors are able to collect more solar energy under a wider variety of ambient conditions Another advantage is the pumping system which allows the system to operate from the electricity generated from a Photovoltaic (PV) panel included with the system.