The electrical consumption of a temperature control system depends much less on the heating than people assume, and much more on the pump and how it is regulated. That's the good news: it's right where you can act. In this article we explain what the consumption of a temperature control unit depends on, which are the five levers that produce the most savings and how to calculate the return of your own installation with your data, not with that of a brochure.
In an injection plant, thermal control of the mold is usually one of the largest electrical consumers that goes unnoticed. Circulation pumps run many hours a day, often at full speed continuously, whether the process requires it or not. That's where the waste and, therefore, the opportunity is concentrated.
How much energy does a temperature control unit consume?
Consumption depends above all on the power of the pump and how it is regulated, rather than on the heating, which only acts to reach the setpoint and compensate for losses. A fixed speed pump always delivers the same flow rate and pressure, whether justified by the process or not, and that excess becomes wasted electricity and heat that must then be removed. Reducing that base consumption is what makes the investment in efficient equipment pay off.
The five levers of energy saving
The equipment is the basis, but the real savings come from combining several measures. These are the five that have the most weight.
1. Variable speed pump
Compared to a fixed speed pump, a regulated pump adjusts flow and pressure to what each process requires. As the power consumed increases sharply with speed, lowering the revs to what is strictly necessary cuts consumption disproportionately. It is, in most installations, the lever with the greatest impact.
2. Correct sizing and flow
Oversizing equipment or moving more flow than necessary does not improve the part and does increase consumption. The objective is the right flow rate to achieve turbulent regime in the mold and maintain the thermal jump between inlet and return within tolerance. Neither more nor less.
3. The choice of fluid and system
Working with water whenever the temperature allows it is more efficient than using oil, because water transfers heat better. At MARSE we manufacture temperature control units —also called thermoregulators or TCU— water with open tank, pressurised water direct and indirect heating, and oil with tank or closed circuit, precisely so that each process uses the most efficient system for its range and not an excess one. A system with a low volume of circulating fluid also requires less energy to heat and cool. If you hesitate between one and the other, you have it developed in water or thermal oil: how to choose the fluid.
4. Flow distribution by circuits
Distributing and monitoring the flow by zones of the mold allows each circuit to be fed in a balanced way and, in many cases, to serve with a single piece of equipment what previously required two. Our solutions multi-circuit distribution and of flow monitoring They are designed for that: less equipment running, same process control and lower consumption.
5. Shorten and insulate hoses
Placing the temperature control unit near the machine reduces the length of the tube, and with it the resistance that the pump overcomes and the heat losses to the environment. The insulation weighs more the higher the temperature of the fluid: above a certain point, the losses through the hoses grow sharply and isolating them is no longer a detail.
How much can you save? An illustrative example
The following calculation is an indicative example with common values in the sector, not a guaranteed figure. Each installation must be measured. Let's assume a medium temperature process in which, adding the switch to a variable speed pump, the correct sizing of the flow and the reduction of equipment for distribution, the electrical consumption of the system drops from about 4 kW to less than 1 kW, that is, around 3.5 kW less.
In three-shift operation, of the order of 6,000 hours per year, and with an electricity price of approximately €0.17/kWh, the savings would be about €3,570 per year per team. In plants with many of the same pieces of equipment, these savings are multiplied. With these specific figures the return is quick, but it is worth insisting: the amortization period depends on the price you pay for energy, your real hours of operation and the starting point of your installation. There is no universal figure.
How to calculate your own return
The formula is simple and you can apply it with your real data:
- Annual savings (€) = power difference in kW (before − after) × operating hours per year × price per kWh
- Return period (years) = investment ÷ annual savings
For the calculation to be reliable, it is necessary measure the actual consumption before and after, not estimate it, because the differences between a fixed pump at full load and a regulated one are usually greater than expected. This approach fits with what we explain in reduced total cost of ownership: What counts is not the purchase price, but what the equipment costs throughout its life.
The savings do not end at the electricity bill
Reducing consumption brings benefits that do not appear on the bill but count just the same. Equipment that does not work at full load suffers less wear, which lengthens its useful life and reduces maintenance. A controlled and stable flow rate improves the repeatability of the process and, with it, the quality of the part and the waste. And less consumption means fewer associated emissions, something increasingly relevant in sustainability strategies and in customer and audit requirements. Overall, energy efficiency and process reliability go hand in hand.
Frequently asked questions
How long does it take to pay for an efficient temperature control unit?
It depends on the avoided consumption, the hours of operation and the price of energy, so there is no valid figure for everyone. In installations that move from fixed speed pumps to well-sized modern equipment, the return is usually quick, but the only correct way to know is to measure consumption before and after and apply the savings formula with your own data.
What saves the most in a temperature control system?
In most cases, the variable speed pump, because the power consumed grows a lot with speed and adjusting it to the necessary flow rate cuts consumption disproportionately. This is followed by correct sizing and equipment reduction through flow distribution.
Does a water or oil temperature control unit consume more?
In its working range, water transfers heat better and usually consumes less, so it is advisable to use water, with a tank or pressurized, whenever the process temperature allows it, and reserve the oil for temperatures that water does not reach.
Does insulating the hoses help?
Yes, especially at high temperatures, where heat losses through the hoses increase rapidly. Shortening them by placing the equipment near the machine, in addition to isolating them, reduces losses and stress on the pump.
Can I reduce the number of temperature control units in my plant?
In many cases yes. With adequate flow distribution and monitoring, what previously required several pieces of equipment can be fed and controlled in a balanced way, maintaining the stability of the process and lowering overall consumption.
Shall we calculate your savings?
At MARSE we have been manufacturing water and oil temperature control units since 1978, with more than 80,000 units installed in more than 70 countries. If you want to know how much you could save in your installation, tell us your process, the hours of operation and your current consumption and we will help you estimate the return with your figures.
Talk to a MARSE technician or scribe to marse@marse.es.
Related readings: temperature control units for injection molds · lime and scale in the mold circuit · connectivity and Industry 4.0.