Cylinder Sizing for Tanks

Finding the Perfect Fit for your Hot Water Needs

In today’s modern homes, meeting hot water demands efficiently requires a cylinder that surpasses the traditional copper tank tucked away in the hot-press. At Greentherm, we understand the importance of accurately sizing cylinders, including buffer tanks and combi cylinders,, to ensure optimal performance for domestic hot water and heating systems. In this post, we will explore the process of cylinder sizing and discuss the considerations involved in finding the right fit for your home.

Calculating the Required Storage Capacity

Determining the appropriate storage capacity is a crucial step in the design process at Greentherm. Based on the plans provided by your architect, we calculate the heat load and hot water demands specific to your home. With this information, we match the requirements with a suitable heat source capable of delivering the desired performance. The buffer tank is then sized based on the most efficient operating point of this heat source and the calculated demands. This meticulous process ensures optimal energy performance while accounting for modern regulations such as Energy Performance and Carbon Performance.

Estimating the Cylinder Dimensions

To illustrate the space required for a cylinder, let’s assume we have determined that a 1000 Litre Thermal Storage tank is necessary to meet your home’s hot water and heating requirements. But how much physical space would this sizable cylinder occupy?

While a cube-shaped tank measuring 1 metre by 1 metre by 1 metre would conveniently hold 1000 Litres of water, most Thermal stores are cylindrical in shape. To estimate the cylinder dimensions, we use the formula for the volume of a cylinder, which is πR²H.

Rearranging the formula, we find the R = √(V/πH), where R represents the radius of the cylinder, V is the volume required (1m³ in this case), and H is the cylinder’s height. Assuming we have enough room for a 1.8-metre tall cylinder, the calculation yields a radius of approximately 43cm.

Considering Additional Space Requirements:

In reality, the cylinder’s width is not solely determined by its radius. Additional factors such as insulation blankets need to be considered. Typically, an insulation blanket adds around 5cm on each side of the cylinder. Consequently, a 1000 Litre cylinder, when finished, would have a width of at least one metre.

However, it’s important to note that this width might pose challenges when it comes to installation, particularly regarding doorways. Tanks like the Jaspi Oval tank have been specifically designed to fit through standard doorways, but most cylinders require special arrangements to ensure a proper fit.

Moreover, sufficient clearance must be allowed for plumbing access, adding another 30-50cm around the sides of the cylinder. Therefore, a 1000 Litre cylinder could require up to 1.3 metres of space in a room for comfortable installation and plumbing.

Recommended Cylinder Capacities:

While a 1000 Litre cylinder is on the larger side, it is still within the realm of possibility. At Greentherm, we typically install buffer tanks in the range of 500 to 800 Litres, while combi-cylinders usually go up to 900 Litres. These capacities provide effective hot water storage and heating solutions for most homes.