Tech Interview

Objectives

Using our Google Sheet Simulator and Europe’s PVGIS API, you will build a small React app (using Typescript) to estimate a solar installation size based on a few parameters.

In other words, you will reverse engineer the current simulator spreadsheet to understand the dimensioning formula and use manual inputs, constants from the GSheet & PVGIS API to get all the parameters needed to compute the result.

You don't need to add a backend app to solve the case. Running the calculations in the frontend is enough.

Project setup

Before starting, you will need to installe NodeJS 18.12 or greater and Yarn. If you have nvm installed (brew install nvm or here):

nvm install 18.12
nvm use 18.12
npm i -g yarn

You can install workspace dependencies by running : yarn

Frontend

You should be able to run frontend on http://localhost:5173 by running:

cd ./packages/frontend
yarn dev

Backend

You should be able to run backend on http://localhost:8000 by running:

cd ./packages/backend
yarn dev

Instructions

Installation size definition

• An installation size means defining the number of solar panels to install on a given roof
• We define a “correct installation size” when the solar panels yearly energy production matches 85% the customer’s yearly energy consumption
• We will use the following material:
  • Panels: DualSun Flash 425 Shingle Black (power: 425Wc)
  • Inverters: Micro-Onduleur Enphase IQ8AC

Parameters & desired output

Program Inputs

• Customer’s address (expressed in GPS coordinates: lat/lon)
• Customer’s electricity monthly bill (€)
• Customer’s roof’s inclination (°) & orientation (cardinal point: W,SW,S,SE etc)

Output

• The number of estimated panels
• The estimated yearly produced energy in kWh

UI

You can choose whatever UI layout you prefer, as long as the UI is neat and easy to navigate. To achieve this, Mantine UI kit has been installed and ready to use.

If you don't know how to start, you can use the following layout as a starting point:

The form fields values should be validated before submitting with the following conditions :

• orientation : one of these values W,SW,S,SE
• inclination : between 0° and 90°
• monthly bill : a positive integer
• coordinates: : floats

Backend

The computation of simulation results should happen in the HTTP resource GET /simulation. You may update this route and both its parameters and response types. You may also validate the parameters before using them.

A few tips

The energy produced by a solar panel depends on multiple transformations:

• The sun energy irradiating the customer’s roof is called “irradiance”, measured in kWh/m2/year
  • The PVGIS API will help you mesure this value for a given address
• The solar panels will receive this energy with a loss ratio, depending of:
  • The system efficiency
  • The photovoltaic panel efficiency
  • The roof’s inclination & orientation
• You can find useful information about efficiencies loss in "Energy Production" tab of the Google Sheet Simulator