Energy consumption of different types of boilers

To acquire boiling water or simply hot water under various circumstances, electric boilers prove to be a convenient option. They come in different variations such as the volume of liquid they heat, functional types, and performance levels. One crucial characteristic to consider for each heating appliance is the power consumption, i.e., the amount of electricity it utilizes. Equally important is determining the current that these boilers consume. The type and magnitude of current determine the applicability of the device in specific operational conditions.

The available boilers can be classified into three distinct categories.

Immersion boilers

An easy, affordable, and well-known kind of appliance for heating liquid. Created with the purpose of producing boiling water in small quantities. In reality, they are intended for boiling no more than 1 liter of water, which is equivalent to 1-2 mugs.

The standard design consists of a metal coil heating element with a cable that connects to an electrical outlet. The coil is submerged in a container filled with water and then removed once the water has reached its boiling point.

Conventional immersion boilers

The power output of immersion boilers available on the market typically falls within the range of 500 to 1500 watts, with seldom any higher. It is rarely justifiable to use electric immersion boilers with higher power ratings. These boilers consume a maximum of 10 amperes from a 220-volt network. However, their productivity is limited. It usually takes between 5 to 10 minutes for a 500-watt device to boil 0.5 – 1 liter of liquid. But if you need to boil 2 liters at once, you would require an electric boiler with a capacity of 1.5 kilowatts.

There are also automobile versions of these boilers available, which can be powered by a constant current supply of either 12V or 24V. They are equipped with a plug that can be inserted into the car’s cigarette lighter socket.

An immersion boilermaker equipped with a car plug is a convenient option for car trips to the countryside. However, its performance is quite low, typically consuming 120 W and taking over 10 minutes to boil just 0.5 liters of water.

These models are often referred to as "boiling mugs" due to their small volume (0.5 – 1 liter) and low-power heating element. However, it is more accurate to classify them as mini kettles.

Advantages:

• Compact size, making it easily portable for trips where other heating devices are unavailable
• Affordability

Disadvantages:

• Low power and performance
• Requires a separate dish for immersion
• Lack of safety features in most models
• Potential fire hazard

One of the main characteristics of these powerful devices is that they are not connected to the water supply network. Instead, water needs to be manually poured into them or pumped in using simple tools. These devices come in sizes ranging from 5 to 40 liters, making them suitable for both industrial and domestic use. However, they are particularly effective in smaller food establishments such as cafes and bars. They are also convenient for employees of small businesses to use. These devices are powered by a 220-volt electrical network.

The heating elements in these devices range from 1 to 3 kW, which corresponds to a current consumption of 5 to 15 amperes.

In order to achieve a productivity level of 30 liters per hour, a heating element with a capacity of 2.5 to 3 kW is required.

Bulk boilers featuring a capacity of 3.2 kW and an hourly output of 30 liters.

When it comes to boilers ranging from 1 to 1.5 kW, their productivity levels are generally not specified. However, it typically does not surpass 15 to 20 liters per hour.

Bulk boilers with a power output of 1.15 kW are available.

Most of these units operate on the "thermopot" principle, meaning that once the water has reached the desired temperature, they maintain the temperature of the entire volume within a specific range. They come with thermoregulators for adjusting different temperature levels. Safety mechanisms prevent the device from operating with insufficient water.

One type of boiler is the geyser-style electric boilermaker designed for brewing tea or coffee. They look very similar externally. In geyser models, the upper part of the strainer is exposed to hot steam from the boiling water. This method is used for coarse coffee and tea varieties.

Geyser-style pour-over boilermaker

Advantages

• Portability. The device can be used outdoors since it is not connected to a water supply. It only requires a 220-volt power source.
• Efficiency. It consumes relatively little electricity and does not need to constantly operate its heating elements.
• Affordability. It is one of the least expensive options among industrial-type devices.

Disadvantages

• Manual water refilling. The water level in the device needs to be monitored and water must be obtained from somewhere to refill the container.
• Low productivity. However, for establishments with 20-30 customers, they are still effective.

The primary distinction is that electric boilers, also known as constant-acting boilers, are permanently connected to the water supply. This category includes the most powerful and productive industrial variations. They are capable of ensuring a constant supply of hot water in large quantities, up to 100 liters per hour or more. Their primary application is in large-scale catering establishments and other public organizations that serve hundreds of individuals.

In such systems, automation monitors the availability of water in the boiler. When hot water is used, the volume is automatically replenished, and the heating process resumes. A drain is required for the resulting condensate.

An estimated scheme of flow boilers

Contemporary designs operate on the concept of progressive heating. A portion of the volume in a separate container is heated until it reaches the maximum temperature, from which it is extracted for utilization. This heating mode results in energy conservation and prevents repeated boiling. By using a mixer in the outlet faucet, it is possible to mix the boiling water with cold water.

These boilers are offered in both countertop and wall-mounted configurations.

Flow-through wall-mounted boilers are available in a 5-liter size, with a power rating of 12 kW and a voltage of 380 V. They have a capacity of 110 liters per hour.

Some models can be connected to a 220 volt power grid, but the more powerful ones need a 3-phase network voltage of 380 volts. The heating elements in these boilers can consume anywhere between 5 to 20 kW of power. This level of power requires a current flow of tens of amperes, which may exceed the capabilities of household wiring.

However, there are also compact flow-through heaters available with a capacity ranging from 3 to 10 liters. Of course, for heating just 5 liters of water, it can be more cost-effective to use pouring boilers. The decision to choose a flow-through heater with these capacities is based on the convenience they offer. Despite their small size and power output of 2 – 3 kW, these heaters can provide up to 20 liters of boiling water per hour without the need for constant refilling. One of the advantages of these small devices is that they can be easily connected to a 220 V power supply.

Flow boilers with a capacity of 3 liters and a power output of 2 kW at 220 V are available.

To achieve high productivity levels of tens of liters per hour, the heaters should have a minimum power output of 10 kW. For instance, a flow boiler with a power output of 13 kW can produce up to 120 liters of boiling water per hour.

One of the most efficient flow boilers on the market can produce 180 liters of boiling water per hour, consuming 19.2 kW of energy.

These devices can only be connected to a three-phase network operating at 380 V.

Flow boilers come in a capacity of 180 liters/hour and a power rating of 19.2 kW, operating at a voltage of 380 V.

Advantages:

• Large volumes and high productivity
• No need for manual refilling
• Complete automation of the heating and boiling process. The automation systems ensure the maintenance of the water level, the desired temperature, the draining of excess portions, and emergency shutdown when necessary.

Disadvantages:

• Requires connection to industrial power grids
• Consumes high amounts of power
• Expensive