Good day Everyone

Hope you all good. I've been up all day trying to figure out my upcoming project System Size. Headache is killing me now ,maths isn't for everyone 🤗. Ok here is the setup of my system. There is 3 water pumps=3 kw three Phase, and 2 of 1,5kw Single phases and the house is pulling 18 kw from the Grid. So considering the start up power for morors I'm doubling the wattage for pumbs to 12kw + 18kw for the house it comes to 30kw.

The client want the pumbs to run even during at night using batteries and also he wants to put panels that will able to supply during the day and charge the battery at the same time.

So my question is how many batteries would be good for the system and panels array (550w) that will operate as specified

Will also appreciate the workout process to learn

 

Thank you

14 hours ago, VictorD said:

Good day Everyone

Hope you all good. I've been up all day trying to figure out my upcoming project System Size. Headache is killing me now ,maths isn't for everyone 🤗. Ok here is the setup of my system. There is 3 water pumps=3 kw three Phase, and 2 of 1,5kw Single phases and the house is pulling 18 kw from the Grid. So considering the start up power for morors I'm doubling the wattage for pumbs to 12kw + 18kw for the house it comes to 30kw.

The client want the pumbs to run even during at night using batteries and also he wants to put panels that will able to supply during the day and charge the battery at the same time.

So my question is how many batteries would be good for the system and panels array (550w) that will operate as specified

Will also appreciate the workout process to learn

 

Thank you

@VictorD

The best and most accurate way of accessing any installation is by measuring the actual amount of energy consumed over a period of 2 to 3 days. I use 3 ph and single ph measuring equipment to do the assessment determining your needs. But here is a ballpark method that you can use but would be not be that accurate due to various factors.

Power Calculation: You've already calculated the total power required as 30 kW, considering startup power for the pumps and the house.

Battery Capacity Calculation: To determine the battery capacity required, you'll need to consider the energy consumption during the night when the pumps are running. Let's say the pumps run for 8 hours at night. So, the energy required is 30 kW * 8 hours = 240 kWh.

Panel Array Calculation: Since the pumps will run during the day as well, you need to ensure that the solar panels generate enough energy to both power the pumps during the day and charge the battery. Let's assume the pumps run for another 8 hours during the day. So, the total energy required during the day is 30 kW * 8 hours = 240 kWh.

Total Daily Energy Generation: You need to generate enough energy to cover both the night consumption and daytime consumption while also charging the battery. Total daily energy generation required is 240 kWh + 240 kWh = 480 kWh.

Solar Panel Output: You mentioned using 550W panels. To calculate the number of panels needed, divide the total daily energy generation by the panel output: 480,000 Wh / (550 W x5.5)=  159 panels.

Battery Capacity: If you want the battery to cover the night consumption of 240 kWh, you'll need a battery with a capacity of at least 240 kWh.

The calculation above is done if no other power generation is possible say for instance no grid power available for a few days so if the site is not critical for longer outages the grid power can be considered in the calculation or other forms of energy can be added eg. Gensets.

Edited September 1, 20232 yr by TaliaB
Edit formula under solar panel output

1 hour ago, TaliaB said:

@VictorD

The best and most accurate way of accessing any installation is by measuring the actual amount of energy consumed over a period of 2 to 3 days. I use 3 ph and single ph measuring equipment to do the assessment determining your needs. But here is a ballpark method that you can use but would be not be that accurate due to various factors.

Power Calculation: You've already calculated the total power required as 30 kW, considering startup power for the pumps and the house.

Battery Capacity Calculation: To determine the battery capacity required, you'll need to consider the energy consumption during the night when the pumps are running. Let's say the pumps run for 8 hours at night. So, the energy required is 30 kW * 8 hours = 240 kWh.

Panel Array Calculation: Since the pumps will run during the day as well, you need to ensure that the solar panels generate enough energy to both power the pumps during the day and charge the battery. Let's assume the pumps run for another 8 hours during the day. So, the total energy required during the day is 30 kW * 8 hours = 240 kWh.

Total Daily Energy Generation: You need to generate enough energy to cover both the night consumption and daytime consumption while also charging the battery. Total daily energy generation required is 240 kWh + 240 kWh = 480 kWh.

Solar Panel Output: You mentioned using 550W panels. To calculate the number of panels needed, divide the total daily energy generation by the panel output: 480,000 Wh / 550 W = approximately 872 panels.

Battery Capacity: If you want the battery to cover the night consumption of 240 kWh, you'll need a battery with a capacity of at least 240 kWh.

I think this calculation could be reduced if one has more detail. For starters, the OP is using double the power of all his pumps combined to determine the pump power demand at 6kW x 2 = 12kW, and then you're assuming that that full start-up demand will run all night, 12kW x 8 hrs, and also that the house's peak demand of 18kW will be running all through the night for 8 hrs. That 18kW sounds over the top for a residence - maybe normal for a home on an 80A circuit breaker to top out at 18kW, but to draw that for baseload sounds unrealistic unless we're talking of wealth beyond my comprehension. My guess is it'll end up being 6kW for the pumps x 8hrs (TBC) - maybe less if some of the pumps must just be available on demand like booster pump when opening a tap - and the inverter surges to 12kW will be transient, and in any case less if the pumps don't have to all start simultaneously. Agreed, though, that actual demand measurement over a period will be the best way to tell.

Edited September 1, 20232 yr by GreenFields

11 minutes ago, GreenFields said:

I think this calculation could be reduced if one has more detail. For starters, the OP is using double the power of all his pumps combined to determine the pump power demand at 6kW x 2 = 12kW, and then you're assuming that that full start-up demand will run all night, 12kW x 8 hrs, and also that the house's peak demand of 18kW will be running all through the night for 8 hrs. That 18kW sounds over the top for a residence - maybe normal for a home on an 80A circuit breaker to top out at 18kW, but to draw that for baseload sounds unrealistic unless we're talking of wealth beyond my comprehension. My guess is it'll end up being 6kW for the pumps x 8hrs (TBC) - maybe less if some of the pumps must just be available on demand like booster pump when opening a tap - and the inverter surges to 12kW will be transient, and in any case less if the pumps don't have to all start simultaneously. Agreed, though, that actual demand measurement over a period will be the best way to tell.

Yep the best way to do these assessments is to actually measure the consumtion for a period of time to comprehend all viarables and to do a geographic study on how solar array would yield. There is actually a lot to consider to have a successful install and not to change or add to the initial install as clients measure you on how successful the intial system is performing and don't appreciate added cost. Correct and factual data is key in system design.