Planning Utility Requirements for Dairy Plants

Once you’ve chosen the right equipment for your dairy plant, there’s a critical next step that often gets overlooked – figuring out exactly how much steam, refrigeration, electricity, water, and compressed air your plant will need. These utilities are the backbone of every dairy operation. Without accurate estimation and reliable supply, even the best equipment will fail to deliver results. Let’s break down how to plan each utility requirement systematically, how to estimate demand, and why standby systems and safety margins are non-negotiable.

Why utility planning matters in dairy processing 🔗

A dairy plant relies on a handful of core utilities to keep things running: steam for heating and sterilisation, refrigeration for product safety, electricity for powering machinery, water for cleaning and cooling, and compressed air for automation and pneumatic controls. Each of these must be available in the right quantity, at the right pressure, and at the right time – or production grinds to a halt.

The challenge is that utility demand in a dairy plant is not constant. It fluctuates throughout the day depending on which equipment is running, which processes are active, and how much product is being handled. Planning utilities effectively means understanding these fluctuations and sizing your systems to handle both average and peak loads comfortably.

Estimating steam requirements 🔗

Steam is the primary heating medium in most dairy plants. It is used for pasteurisation, sterilisation, CIP (cleaning-in-place) systems, and heating water for various process needs. In a typical dairy, the steam temperature in the distribution system must be maintained between 140 and 150°C, which corresponds to a gauge pressure of roughly 2.7 to 3.8 bar for saturated steam.

Plotting a steam load diagram 🔗

The most effective way to estimate steam demand is by plotting a steam load diagram – a chart that maps the steam consumption of every piece of equipment against a daily time scale. Here’s how it works:

First, list every steam-consuming piece of equipment in the plant – pasteurisers, CIP units, sterilisers, jacketed tanks, bottle washers, and so on. For each item, note its steam consumption rate (in kg/h) and the time window during which it operates. Then, plot these on a time axis covering a full production day. Where multiple pieces of equipment run simultaneously, their steam demands stack up, creating peaks in the diagram.

The highest point on this diagram represents your peak steam demand. The average across the day gives you the base load. Your boiler capacity must be sized to handle the peak demand reliably. According to industrial boiler sizing guidelines, it’s standard practice to add a safety margin of 10-20% above the calculated peak steam requirement to account for unexpected surges, system losses, and future expansion.

Boiler efficiency and heat losses 🔗

Keep in mind that not all the energy generated in the boiler makes it to your equipment. Boiler efficiency typically falls in the range of 80-92%, and heat losses in the piping system can amount to around 15%. That means only about 65-77% of the total fuel energy is actually utilised in production. Monitoring boiler efficiency closely is essential for keeping operating costs under control.

Additionally, when planning the steam network, heat losses in the piping must be factored into the steam output design. For well-insulated pipework, a rough estimate is about 10 kg of steam lost per hour for every 100 metres of pipe. Poorly insulated or uninsulated lines will waste significantly more.

Estimating refrigeration requirements 🔗

Refrigeration is critical for maintaining the quality and safety of milk and dairy products at every stage – from raw milk reception to cold storage of finished goods. The operating costs of the refrigeration plant represent one of the most significant budget items in any dairy.

Calculating the cooling load 🔗

The total refrigeration requirement is estimated by calculating the cooling load, which includes three main components:

Product cooling load: This is the heat that must be removed from milk and other dairy products during processing and storage. It depends on the volume of product, its incoming temperature, and the target temperature.

Environmental heat gain: Heat entering refrigerated spaces from the surrounding environment through walls, ceilings, doors, and floors. Insulation quality and ambient temperature play a big role here.

Equipment heat gain: Heat generated by motors, lighting, and other machinery operating inside refrigerated spaces.

Adding up all three components gives the total cooling load, expressed in kilowatts or tonnes of refrigeration (TR). This determines the capacity of compressors, evaporators, and condensers you’ll need. As a reference, the FAO notes that refrigeration of one tonne of milk product typically requires 100-120 MJ of electrical energy in modern medium and large-scale collection centres.

Choosing condensers and evaporators 🔗

Condenser selection depends on external factors such as local water availability, water cost, plant operating hours, and climate. Air-cooled condensers are becoming more common in large plants due to rising water costs and supply uncertainty. Water-cooled condensers remain the more economical choice where cheap, reliable water supply is available. Evaporators in dairy plants – typically shell-and-tube or plate-type – extract heat from circulating coolants like ice water, brine, or glycol solutions that cool products in process heat exchangers.

Some plants also use ice bank systems, where ice is accumulated on evaporator coils during off-peak hours (often overnight, when electricity is cheaper). This stored cooling capacity is then released during peak production hours, helping to balance the refrigeration load and reduce energy costs.

Estimating electricity requirements 🔗

Electricity powers nearly every aspect of a dairy plant – from pumps, homogenisers, and separators to lighting, control systems, ventilation, and refrigeration compressors. According to industry data, about 80% of a dairy’s total energy consumption goes toward generating steam and hot water, while the remaining 20% is consumed as electricity for mechanical processes, refrigeration, ventilation, and lighting.

How to estimate electrical demand 🔗

To estimate your plant’s electrical needs, start by listing every electrically powered piece of equipment along with its rated power consumption (in kW). Then, determine the daily operating hours for each. Multiply power rating by operating hours to get the daily energy consumption (in kWh) for each item.

However, not all equipment runs at the same time. Use a demand factor (also called a diversity factor) to account for the fact that only a portion of the total installed electrical load is active at any given moment. The peak electrical demand – the highest simultaneous load – determines the capacity of your main transformer, switchgear, and backup power systems.

It’s important to also account for power factor correction. Inductive loads like motors and compressors draw reactive power, which reduces the efficiency of your electrical system. Power factor correction capacitors help minimise this issue and can lower your electricity bills.

Estimating water requirements 🔗

Water is used extensively in dairy plants for product processing, equipment cleaning (CIP and manual), cooling, boiler feed, and sometimes as a direct ingredient. The ratio of water used to milk handled typically ranges from 1:1 to 2:1, depending on the types of products being manufactured.

Key considerations for water supply 🔗

Pressure and flow: Dairy applications often require large volumes of water at sustained high pressure over short periods. Multiple outlets may draw water simultaneously – for CIP, bottle washing, and cooling – causing pressure drops if the system is undersized. Pressure tanks or frequency-controlled pumps can act as accumulators to manage these instantaneous load spikes.

Water quality: Water used in product manufacturing must exceed drinking water standards – it should be clear, odour-free, soft, and virtually sterile. Boiler feed water must also be softened to prevent scale formation on heating surfaces, which is both a safety hazard and a source of energy waste.

Reducing consumption: Minimising water usage directly reduces the load on effluent treatment systems. Modern plants are increasingly adopting water recovery measures such as condensate recovery, white water recovery, and membrane filtration to reclaim usable water from process streams.

Estimating compressed air requirements 🔗

Compressed air is sometimes called the “fourth utility” in dairy processing, after gas, water, and electricity. It powers pneumatic valves, actuating cylinders, filling machines, conveyor systems, and instrument control systems. In highly automated modern dairies, reliable compressed air supply is essential for continuous operation.

Pressure and quality requirements 🔗

Most pneumatic equipment in a dairy plant requires compressed air at approximately 600 kPa (6 bar). To compensate for pressure drop across the distribution system, the compressor plant should produce air at an operating pressure of about 700 kPa (7 bar). Rather than running separate compressors for different pressure needs, the most practical approach is a single compressor plant with a single distribution network.

Air quality is equally important. Compressed air that comes into direct contact with dairy products – for example, during tank agitation or pipe emptying – must be filtered, dried, and sterilised before use. Untreated compressed air contains moisture, oil particles, and microorganisms that can contaminate products. The air must be contaminant-free to meet food safety standards, and point-of-use sterile filters are fitted immediately before the equipment where the air is used.

The role of standby systems 🔗

In a dairy plant, certain utility failures can cause immediate and irreversible damage. If refrigeration goes down, milk and products can spoil within hours. If steam supply fails during pasteurisation, an entire batch may need to be discarded. A compressed air failure can shut down every pneumatic valve in the plant, halting production entirely.

This is why standby (backup) systems are essential for critical operations. Standby systems include backup boilers, additional refrigeration compressors, emergency diesel generators for power, and reserve air compressors. The principle is simple – if the primary system fails, the standby kicks in with minimal disruption.

For refrigeration, many plants maintain built-in redundancy by installing multiple smaller compressors rather than a single large unit. If one compressor fails, the others continue running while repairs are made. Similarly, for electricity, an uninterruptible power supply (UPS) or standby generator ensures that control systems and critical equipment stay online during grid outages.

Why safety margins are non-negotiable 🔗

Even with accurate calculations, real-world conditions are never perfectly predictable. Equipment may run longer than expected, ambient temperatures may spike during summer, or a new product line may increase utility demand. This is why every utility system in a dairy plant should be sized with a safety margin – typically 10-20% above the calculated peak demand.

This margin provides a buffer that absorbs unexpected surges without overstressing equipment. It also accommodates future plant expansion without requiring a complete overhaul of utility infrastructure. An undersized system that operates at its maximum capacity all the time wears out faster, runs less efficiently, and is more prone to breakdowns.

At the same time, excessive oversizing is wasteful. A boiler that’s far too large for the actual load will short-cycle – frequently turning on and off – which reduces combustion efficiency and increases maintenance costs. The goal is to find the right balance: enough capacity for peak loads and future growth, but not so much that the system runs inefficiently during normal operations.

Bringing it all together: a practical approach 🔗

Planning utilities for a dairy plant is a systematic process. After finalising equipment selection, follow these steps:

Step 1: List every piece of equipment and its utility requirements – steam consumption, electrical load, water usage, refrigeration load, and compressed air demand.

Step 2: Map each equipment’s operating schedule across a 24-hour production cycle.

Step 3: Plot load diagrams for each utility, identifying peak demands and base loads.

Step 4: Add system losses (pipe heat losses, pressure drops, electrical transmission losses) to your calculated demands.

Step 5: Apply a safety margin of 10-20% to the peak demand for each utility.

Step 6: Identify critical operations and plan standby systems for each essential utility.

Step 7: Validate the design against industry standards and local regulations.

This process ensures that every utility system is right-sized – large enough to handle worst-case scenarios but efficient enough for everyday operations.

What do you think? How would you prioritise utility investments if you were designing a dairy plant on a limited budget – would you put more resources into redundancy for refrigeration, or would you focus on energy-efficient steam generation to control long-term operating costs?

References

1. https://dairyprocessinghandbook.tetrapak.com/chapter/service-systems
2. https://coalbiomassboiler.com/industrial-steam-boiler-sizing-guide/
3. https://www.boiler-planning.com/en/planning/steam-output/calculation-of-consumption.html
4. https://www.fao.org/4/t0515e/t0515e03.htm
5. https://dairyprocessinghandbook.tetrapak.com/chapter/sustainability-dairy-processing
6. http://ecoursesonline.iasri.res.in/mod/page/view.php?id=124103
7. https://www.dairyfoods.com/articles/90762-compressed-air-is-a-dairy-processors-fourth-utility
8. https://www.airbestpractices.com/industries/food/three-types-food-industry-compressed-air-systems