Solar Water Heating - Economic Feasibility Study
Domestic solar water heaters are seen as one of the most cost effective renewable energy options in many parts of the world.
Solar water heating systems cost more to purchase and install than conventional water heating systems. However, a solar water heater can usually save you money in the long run. This depends on many factors such as the initial cost of the system, solar radiation and the cost of fuel/ electricity.
Try out our tool for to estimate the feasibility of installing a domestic solar water heating system.
NOTES:
* Denotes a recommended value
Numbers in brackets are negative
Conversion of Units
Assumptions About The Solar Heating System
You can make changes that you deem necessary
Flat Plate Solar Collectors are widely used in domestic water heating installations. Evacuated tube collectors are more expensive and typically used in larger, commercial applications due to their higher efficiency.
It is the total size of the surface of the solar collector that faces the sun.
The area over which the solar radiation enters the collector.
How much sun's energy can the solar collectors convert into heat. In other words, what comes out of the collectors.
General Information
It is widely accepted that the value of money today is greater than its value in the future. This means that money received at a later time is not as valuable as the same amount received today. This concept is not related to inflation, hence even if inflation is zero, we would still prefer to receive money today than the same amount of money after some time. This is primarily because we can put the money to use today in various ways such as learning a new skill, purchasing a laptop for work, or investing the money to watch it grow.
This tool helps in calculating the present value of future cash flows. The discount rate determines the value of future benefits; a higher discount rate implies that the value of benefits decreases with time. Simply speaking, you may use the interest rate offered by commercial banks on deposits as the discount rate. If you don't want to discount future cash flows, you can set the discount rate to zero.
Domestic Hot Water (DHW)
The tool allows for a temperature up to 70 °C.
Solar Water Heating
The portion of the total heating load delivered by solar energy.
Construction & Operation Costs
Loan Details
If you are not taking a loan to finance this project, set the fields below to zero.
Savings
Results
| Domestic Hot Water (DHW) | |
|---|---|
| Needed daily hot water (gallons) | |
| Needed daily hot water (kg) |
| Required Energy - Typical Heater | |
|---|---|
| Temperature difference (°C) | |
| Energy required to raise temperature (kWh) |
| Solar Water Heating | |
|---|---|
| Average hot water from solar (kg) | |
| Heat required to raise temperature (kWh) |
| Solar Heating - System Size | |
|---|---|
| Number of solar collectors | |
| So, actual aperture area in m² | |
| Solar collectors' gross area in m² |
| Savings
Compared to heating same amount of water using electric heater(s) |
|
|---|---|
| Daily energy savings (kWh) | |
| First year energy savings (kWh) | |
| First year energy savings () |
| Runningn Costs | |
|---|---|
| First year maintenance cost | |
| Loan yearly payment |
| Investment Breakdown | |
|---|---|
| Solar system cost | |
| Initial Investment | |
| Loan principal payment | |
| Interest | |
| Opex |
| Should I Just Save My Money?
Assuming the interest rate is equivalent to the discount rate |
|
|---|---|
| Invested money | |
| Saving account after years |
Expenses (%)
Cumulative Cash Flow ()
Cumulative Discounted CF ()
| Year | Energy Cost () | Savings (kWh) | Savings () | Loan Payment () | Running Costs () | Total Costs () | Cash Flow () | Cumulative Cash Flow () | Discounted Savings () | Discounted Costs () | Discounted CF () | Cumulative Discounted CF () |
|---|
Input
| Conversion of Units | |
|---|---|
| US gallon into litre or kg | |
| Joule into kWh | |
| Water - specific heat capacity (J/g°C) | |
| Specific heat capacity in "kWh/ kg °C" | |
| kWh into BTU |
| Assumptions About The Solar Heating System | |
|---|---|
| Collector type* | |
| Collector’s gross area in m²* | |
| Collector’s aperture area in m²* | |
| Efficiency of the solar collectors* | |
| Losses in pipelines and storage tank* |
| General Information | |
|---|---|
| Currency | |
| Electricity (USD/ kWh) | |
| Annual perecntage increase in electricity | |
| Discount rate |
| Domestic Hot Water (DHW) | |
|---|---|
| Number of people | |
| Daily hot water per person (gallons)* |
| Required Energy - Typical Heater | |
|---|---|
| Water temperature in (°C) | |
| Targeted water temperature (°C)* | |
| Heater efficiency* |
| Solar Water Heating | |
|---|---|
| Average daily radiation (kWh/m²/day) | |
| System life-time* | |
| Solar contribution ratio* |
| Construction & Operation Costs | |
|---|---|
| Solar system cost per m² (USD) | |
| First year maintenance (% of system cost) | |
| Yearly percentage increase in maintenance cost |
| Loan Details | |
|---|---|
| Loan period in years | |
| Borrowing interest rate | |
| Equity ratio |
Output
Cumulative Cash Flow ()
Cumulative Discounted CF ()
Expenses (%)
