Table of content
NPH House Research Test
NPH Test Results

NPH House Research Test

1. Research Question

How does the NPH system affect the external and internal temperatures of the house?

2. Research Objective

2.1 Main Objective:

To measure the temperature of the NPH house at various times of the day under different scenarios, including:

  1. House NPH with 3 components (underground cooling, AFB walls, cat hole)
  2. House NPH with 2 components (underground cooling, AFB walls)
  3. House NPH with 1 component (AFB walls)

2.2 Specific Objectives:

  1. To measure the temperature difference between underground (Underground system) and above-ground (Ambient temperature) in NPH houses with 2 and 3 components (as mentioned in 2.1)
  2. To measure the efficiency of air expansion at the walls (Thermo expansion effect) on the efficiency of drawing cool air from underground in both open (Open system) and closed systems (Closed system)
  3. To measure the energy-saving efficiency of the NPH house in both open (Open system) and closed systems (Closed system)

This research test was conducted on a newly built house in Sa Kaeo province with a 3-component NPH system (no ceiling convection). The project owner allowed the installation of testing equipment from November 26-27, 2024, at the Double A project in Wang Nam Yen, Sa Kaeo Province.

Testing Method

  1. Construct the actual house according to the 4 conditions of the NPH house principle.
  2. Calculate the underground cooling pipe system suitable for the designed house.

3. Install the Underground Cooling System as calculated.

Research House in Sa Kaeo Province

4. Install the air cooling pipe system at the bottom of the AFB walls.

5. Install temperature sensors at various points to measure the temperature and record data through the IoT (Internet of Things) system, reading real-time data every 5 minutes for further analysis.

Sensor Installation Positions

NPH Test Results

Test 1 The “ON” and “OFF” tests of the NPH system.

Test 2 Whether the NPH system can induce cool air from the underground pipe system.

Test 3 “CLOSE” house “OFF” NPH system <> “OPEN” house “ON” NPH system.

Test 4 Comparing the temperature in the middle of the house between the ON and OFF NPH systems.

Test 5 Testing the NPH system ON and OFF for 5 consecutive days.

Test 6 The performance of air expansion according to scientific principles.

Test Results 1

Open 6 Test Results (73 Minutes)

Summary: In the open and closed house situation, opening the NPH system worked better than closing it. It resulted in better temperature management within the house, with a 30% improvement, and reduced the hours the house temperature exceeded 30°C by more than 2 times.

Summary: The self-draft induced by the NPH system worked efficiently according to the hypothesis. The underground temperature could be used to adjust the temperature of the walls effectively.

Summary: Opening the NPH system is more effective in reducing the temperature inside the house compared to closing the system. This allows the house to stay cool and comfortable for a longer period than when the system is off.

Summary: Opening the house and the NPH system provides the most efficient cooling for the house.

Summary: Opening the NPH system reduces the temperature inside the house by about 25% compared to when the system is off. It also keeps the temperature lower for approximately twice the time, resulting in significant energy savings.

Summary: The air expansion principle caused the buoyant pressure to rise as expected scientifically. By opening the NPH system, the temperature of the walls was reduced by 2-4°C, making the house cooler and more energy-efficient.

Summary of Overall Test Evaluation

The innovation of energy-saving Air Flow Blocks (AFB) combined with natural passive house techniques (NPH) helps to reduce the temperature inside the house and maintains a comfortable temperature for a longer period. Energy savings are increased by about 20-30%. If both AFB energy-saving bricks and NPH houses are widely used, energy consumption could be reduced by approximately 1,700 – 2,400 million baht per year.