Sustainable Water Heating for Popular Rose Nursery

Like all horticultural facilities, rose nurseries require a lot of water and are very dependent on stable temperatures across the site. This popular rose nursery provides at least 10 different varieties of roses, all in common colors and with various stem lengths, they also cultivate a number of exclusive varieties. The greenhouse houses 15,000 plants. Each plant receives nutrients through a tube, and the drain water is analysed every two weeks in a lab for the necessary nutrients. Adjustments can be made if necessary. Pests are organically repelled from the greenhouse using predatory mites, a natural enemy of spider mites and thrips.

The climate was also a key reason for choosing a sustainable hot water system. This rose nursery is currently one of few rose growers to regulate the greenhouse temperature with a heat pump and a buffer tank holding no less than 130,000 litres of water. The heat pump is powered by electricity from solar panels and, during the day when the sun is shining, heats the water to a temperature of 50 °C. A large tank such as this is a perfect way to store the sustainably generated energy in water. This ensures that the greenhouses maintain the correct temperature for most of the year. To ensure operational reliability, a gas‑fired system has been installed as a backup in case it gets exceptionally cold outside.

A buffer tank of 130,000 litres of water heated to 50 °C by the Amicus Low Temperature air-source heat pump required a long warm‑up time during commissioning. We also split commissioning into two phases: first, the installation and initial setup of the heat pump (which went perfectly), and then a follow‑up a week later to verify the water had reached the desired temperature. Once that temperature is achieved, it’s then vitally important to maintain it consistently.