PTC Electric Boiler Guide - Part I

Application of PTC Heating Elements in Electric Heating Boilers (Part 1): Advantages and Structural Types

Introduction

As clean heating solutions continue to replace traditional coal-fired systems, electric heating boilers equipped with PTC (Positive Temperature Coefficient) heating tubes have gained widespread attention. Understanding the fundamental pros and cons of electric boiler heating, as well as the structural configurations of heating tubes, helps engineers and users select the right system for residential and commercial space heating.

1. Advantages and Disadvantages of Electric Boiler Heating

Transitioning from coal to electricity offers clear environmental and practical benefits, alongside a few operational considerations:

• Clean and Eco-Friendly: Electric boilers eliminate coal combustion, significantly reducing harmful emissions and smog-forming pollutants.

• Simple and Cost-Effective Setup: They feature a straightforward structure, safe operation, and low initial equipment cost. More importantly, existing radiators and piping from previous coal-fired heating systems can be directly reused without major retrofitting.

• Operational Challenges: The primary drawbacks are slightly higher running costs (electricity expenses) and potential electrical leakage risks if the heating elements are not properly designed or maintained.
  
  

2. Three Structural Types of Electric Heating Boilers

Depending on how the PTC heating tube interacts with water and how water circulates through the indoor radiators, electric boilers are generally categorized into three structural types:

Type 1: Immersion Heating Tube (Tank-Type)



In this configuration, the heating tube is inserted directly into a water tank to heat the water, which is then pumped to indoor radiators via a hot water outlet pipe and returned through a return pipe.

• Pros: Scale buildup on the surface of the heating tube is easy to clean. In addition, because it includes an insulated water tank, users can take advantage of off-peak electricity rates to heat and store water, substantially reducing electricity bills.

• Cons: It requires a dedicated insulated water tank, which increases manufacturing costs, takes up more floor space, and requires a longer pre-heating time after power-on before indoor heating begins.
  
  

Type 2: Flow-Through Heating Tube with Pump Circulation



Instead of heating water inside a storage tank, water is heated directly as it flows through the heating tube, driven by a circulation pump. The heating tube can be installed at any angle.

• Pros: Eliminates the need for a water tank, resulting in lower equipment cost, a compact footprint, and rapid heating. It is particularly suitable for small-area, low-power indoor heating applications.

• Cons: Scale inside the system is harder to clean. While a water tank is optional, operating without one means the system cannot store heat using off-peak electricity.
  
  

Type 3: Thermosiphon (Heat-Driven) Circulation


In this pump-free flow-through design, the heating tube is mounted vertically. As water inside the tube is heated, its temperature rises and its specific gravity decreases, causing the hot water to naturally flow upward into the radiator system.

• Pros: Operates silently with zero water pump noise.

• Cons: Relies on natural thermal convection, resulting in lower water flow pressure and slower flow velocity, which makes the system more prone to scale deposition.
  
  

Conclusion

Choosing between immersion tank-type, pump-driven flow-through, and thermosiphon electric boilers depends on space availability, noise sensitivity, and whether off-peak power storage is a priority.

In Part 2 of this series, we will explore how to select the right water-contact materials (aluminum, copper, stainless steel, and titanium) and optimal power density for PTC heating tubes.