At Kipp & Zonen we receive a lot of questions from customers wanting to know about measuring solar irradiance for PV projects. This could be for solar resource mapping or site prospecting; or in the design, construction or operational phases of a power plant. What monitoring equipment should they buy?
Measuring the available solar irradiance accurately and reliably is key to assessing site viability, plant efficiency and performance ratios. Most frequently this is for fixed angle PV module installations but tracking systems are becoming more popular, particularly single-axis tracking.
There are international standards, such as IEC 61724-1, Photovoltaic system performance – Part 1: Monitoring (March 2017) and many of the established companies and organisations in the solar energy market have developed their own guidelines and procedures. However, each situation is unique with different influences affecting the selection of instruments; the phase of the project, technology and capacity, geographical and environmental factors, and more.
This can be very confusing, particularly for those new to the market or with less experience!
Our new configurator
As a result of consultation with current and potential customers we have developed a new step-by-step online tool to recommend the most appropriate Kipp & Zonen instruments for PV projects, our Solar Irradiance Measurement Configurator.
By answering a set of questions you describe your project and its phase and become aware of the best way to monitor the available solar energy and the performance of the project. We regularly get the question ‘How many pyranometers do I need?’ and the configurator also suggests answers to this. At the end of the process you get a ‘shopping list’ of the products that we believe best fit the PV project described.
Once you complete the configuration steps you will see the recommendation on your screen. Just leave your email address and you will receive a message with a pdf of the shopping list attached and an encouragement to contact your local Kipp & Zonen representative for further information
Please note that at the moment the configurator runs on Chrome, Safari and Firefox browsers; but not on Internet Explorer or Edge.
How does it work?
When you start the configurator you will see step-by-step windows come up as you click on the various selection options.
You will see that many of the selections available have by them a letter ‘i’ in a circle. You can click on this for more information, which opens in a separate window with a ‘CLOSE’ button at the bottom of the window.
There is always a ‘BACK’ arrow to return to the previous page and you can ‘START OVER’ to return to the beginning.
Dividing your solar power plant into sections
Smaller PV plants generally have all the PV modules fixed at the same tilt angle and orientation, but this is not always the case as plants get larger. They may be installed on sloping ground or across hillsides that can have many different tilts and orientations of the panels.
In this case it will be necessary to divide the plant into a number of sections for the most common module angles and to use the configurator for each of these sections of the plant.
This would also apply to plants where some areas have different effects from near or far shading.
Name your project
You can give each project, or section of a project, a different name so that you can easily find them from multiple configurations that you have made.
Choose the project phase, technology and size
There are three options for the phase of your PV project; ‘Prospecting’ for sites (or resource mapping), ‘Design’ of a solar power plant and ‘Constructing’ or ‘Operating’ the plant. For each of these you can choose modules at a fixed tilt and orientation or mounted on sun trackers (one or two axis).
Choose kW or MW and enter the plant capacity, this is one of the inputs into estimating the number of measurement instruments required and is typically the designed theoretical capacity and not the actual yield. Up to 1 MW (1000 kW) you will be asked whether your solar plant is a commercial rooftop installation. Rooftop plants larger than this are unusual and are treated in the same way as a ground-mounted utility plant.
Instrument types, measurement quality and sun trackers
Depending upon the project description, instruments will be offered for a variety of solar irradiance measurements.
Pyranometers for global horizontal irradiance (GHI), shaded on a sun tracker for diffuse horizontal irradiance (DHI) or mounted at the same tilt angle and orientation as PV modules for plane of array (POA) irradiance. Pyrheliometers mounted on a sun tracker for direct normal irradiance (DNI).
Three types of sun trackers are available to choose from; the RaZON+ all-in-one solution, the versatile SOLYS2 and the heavy duty SOLYS Gear Drive.
The required instrument output can be selected. This can be the low-level mV output from the ‘Classic’ CMP series pyranometers and CHP1 pyrheliometer or the Modbus® digital output of the ‘Smart’ SMP and SHP1 models. Two Smart analog outputs are also choices, 4-20 mA (-A versions) or 0-1 V (-V versions).
You can select from ‘Basic’ entry level monitoring, or the generally accepted ‘Industry standard’ that is normally used for efficiency and performance ratio calculations, or the ‘Best’ currently achievable. For systems with sun trackers it does not make sense to use basic performance instruments, so only industry standard and best are shown as selections.
Your shopping list
When you get to the end of your configuration you will see a list of the recommended Kipp & Zonen products and the suggested quantities of each. There is also a list of additional products that could be useful, such as the CVF4 ventilation unit and the DustIQ soiling monitoring system.
Press the ‘Receive your shopping list by email’ button and enter your email address, the results of your configuration will be sent as a pdf to your email inbox.
Have fun with our new configurator and please let us know your feedback so that we can continue to improve it in the future.