Difference between revisions of "Load and solar resource comparison"

From Open Source Solar Project
Jump to navigation Jump to search
(Marked this version for translation)
 
(7 intermediate revisions by the same user not shown)
Line 1: Line 1:
 
[[Category:Site evaluation]]
 
[[Category:Site evaluation]]
−
The design process for an off-grid PV system should use conservative, worst-case values to ensure that the system is capable of meeting the energy needs of users throughout the year. There are many locations that have a significant seasonal variance in [[Weather and solar resource evaluation|solar resource]] due to poor weather or latitude. Many off-grid PV systems will see a significant variance in [[Load evaluation|how loads are used throughout the year]], especially in locations that are only seasonally occupied. These two different factors - load usage vs. solar resource - make it important to determine what month to use in the system design as the worst-case scenario. An analysis of loads and usage could be performed on a monthly basis, but the most drastic shift in usage likely occurs between the major seasons in a given region meaning two to four times per year. Determining the worst-case month can be done using a simple table and a quick calculation. The values and calculation can be performed in Wh or kWh - the ratio is what is important. The two following values used for the design should be chosen from the month with the highest ratio of average daily watt-hours relative to average monthly insolation:
+
<languages />
 +
<translate>
 +
<!--T:1-->
 +
The design process for an off-grid PV system should use conservative, worst-case values to ensure that the system is capable of meeting the energy needs of users throughout the year. There are many locations that have a significant seasonal variance in [[Special:MyLanguage/Weather and solar resource evaluation|solar resource]] due to poor weather or latitude. Many off-grid PV systems will see a significant variance in [[Special:MyLanguage/Load evaluation|how loads are used throughout the year]], especially in locations that are only seasonally occupied. These two different factors - load usage vs. solar resource - make it important to determine what month to use in the system design as the worst-case scenario. An analysis of loads and usage could be performed on a monthly basis, but the most drastic shift in usage likely occurs between the major seasons in a given region meaning two times per year. Determining the worst-case month can be done using a simple table and a quick calculation using [[Special:MyLanguage/Weather and solar resource evaluation|monthly insolation data]] and [[Special:MyLanguage/Load evaluation|Average daily Wh estimates]] for the two different time periods October - March and April - September. The two following values used for the design should be chosen from the month with the highest ratio of average daily watt-hours relative to average monthly insolation:
  
 +
<!--T:2-->
 
*Design daily insolation
 
*Design daily insolation
 +
 +
<!--T:3-->
 
*Design daily watt-hours required
 
*Design daily watt-hours required
  
−
====Step 1: Determine monthly ratio of consumption to solar resource====
+
====Step 1: Determine monthly ratio of energy demand to solar resource==== <!--T:4-->
  
 +
<!--T:5-->
 
{| class="wikitable" border=1
 
{| class="wikitable" border=1
 
!Month
 
!Month
−
![[Weather and solar resource evaluation#Solar resource (insolation)|Average daily insolation]]
+
![[Special:MyLanguage/Weather and solar resource evaluation#Solar resource (insolation)|Average monthly insolation (kWh/m²)]]
−
![[Load evaluation#Average daily watt-hours required|Average daily watt-hours required]]
+
![[Special:MyLanguage/Load evaluation#Total average daily energy demand|Total average daily energy demand (Wh)]]
 
!Ratio
 
!Ratio
 
|-
 
|-
Line 32: Line 39:
 
|
 
|
 
|
 
|
−
|
+
|-
 
|May
 
|May
 
|
 
|
Line 74: Line 81:
 
|}
 
|}
 
*'''Month:''' The month of the year.
 
*'''Month:''' The month of the year.
−
*'''Average daily insolation:''' Solar resource data obtained for the location from [[Weather and solar resource data sources]].
 
−
*'''[[Load evaluation#Average daily watt-hours required|Average daily watt-hours required]]''' from load evaluation.
 
−
*'''Ratio =''' Average daily watt-hours required ÷ Average monthly insolation
 
  
−
====Step 2: Determine design values====
+
<!--T:6-->
 +
*'''Average monthly insolation:''' Solar resource data obtained for the location from [[Special:MyLanguage/Weather and solar resource evaluation|Weather and solar resource evaluation]].
 +
 
 +
<!--T:7-->
 +
*'''[[Special:MyLanguage/Load evaluation#Total average daily energy demand|Total average daily energy demand]]''' for the month from the load evaluation.
 +
 
 +
<!--T:8-->
 +
*'''Ratio =''' Total average daily energy demand ÷ Average monthly insolation
 +
 
 +
====Step 2: Determine design values==== <!--T:9-->
  
 +
<!--T:10-->
 
{| class="wikitable" border=1 style="width: 80%;"
 
{| class="wikitable" border=1 style="width: 80%;"
−
! style="width: 20%"|Design daily insolation
+
! style="width: 20%"|Design daily insolation  
−
! style="text-align:left;"| = Average monthly insolation from month with the highest ratio ÷ 30
+
! style="text-align:left;"| = Average monthly insolation (kWh/m²) from month with the highest ratio ÷ 30
 
|}
 
|}
  
 +
<!--T:11-->
 
{| class="wikitable" border=1 style="width: 80%;"
 
{| class="wikitable" border=1 style="width: 80%;"
 
! style="width: 20%"|Design daily watt-hours required
 
! style="width: 20%"|Design daily watt-hours required
−
! style="text-align:left;"| = Average daily watt-hours from month with the highest ratio
+
! style="text-align:left;"| = Total average daily energy demand (Wh) from month with the highest ratio
 
|}
 
|}
  
−
==Notes/references==
+
==Notes/references== <!--T:12-->
 
<references/>
 
<references/>
 +
</translate>

Latest revision as of 14:19, 1 April 2021

Other languages:
English • ‎español

The design process for an off-grid PV system should use conservative, worst-case values to ensure that the system is capable of meeting the energy needs of users throughout the year. There are many locations that have a significant seasonal variance in solar resource due to poor weather or latitude. Many off-grid PV systems will see a significant variance in how loads are used throughout the year, especially in locations that are only seasonally occupied. These two different factors - load usage vs. solar resource - make it important to determine what month to use in the system design as the worst-case scenario. An analysis of loads and usage could be performed on a monthly basis, but the most drastic shift in usage likely occurs between the major seasons in a given region meaning two times per year. Determining the worst-case month can be done using a simple table and a quick calculation using monthly insolation data and Average daily Wh estimates for the two different time periods October - March and April - September. The two following values used for the design should be chosen from the month with the highest ratio of average daily watt-hours relative to average monthly insolation:

  • Design daily insolation
  • Design daily watt-hours required

Step 1: Determine monthly ratio of energy demand to solar resource

Month Average monthly insolation (kWh/m²) Total average daily energy demand (Wh) Ratio
January
February
March
April
May
June
July
August
September
October
November
December
  • Month: The month of the year.
  • Ratio = Total average daily energy demand ÷ Average monthly insolation

Step 2: Determine design values

Design daily insolation = Average monthly insolation (kWh/m²) from month with the highest ratio ÷ 30
Design daily watt-hours required = Total average daily energy demand (Wh) from month with the highest ratio

Notes/references

Retrieved from "http://www.opensourcesolar.org/w/index.php?title=Load_and_solar_resource_comparison&oldid=12257"