## 1 Introduction
Since almost all the tubular houses are built in the form of townhouses, the shape factor can be decreased, and the heat loss from the external surfaces can be reduced. Furthermore, two yards enable a reduction in the heating load by introducing sunlight and a reduction in the cooling load by providing ventilation. Thus, it has a positive effect on the energy conservation. If the tubular house can be inherited as a component in the process of urbanization, it will aid in energy conservation and natural ecosystem protection in southern China. Figure 1: _Cont._  
In the past decade, extensive work has been carried out to reveal the thermal mechanisms of tubular houses. A team from the South China Institute of Technology [27] studied the basic principles of insulation and ventilation of tubular houses in Guangzhou. [PERSON] [28] studied the relationship between ventilation, wind pressure, and thermal compression in tubular houses. [PERSON] [29] proposed that increasing the height of the yard could increase the ventilation effect of tubular houses. [PERSON] [30] studied the relationship between the yard area and the energy consumption of tubular houses in Fujian. The famous Indian architect [PERSON] [31] indicated that tubular houses should improve the wind effect of the atrium in the yard to promote indoor ventilation. However, considering the research methodology and technique strategy, numerous researchers have focused on the impact of architectural forms and ventilation. Unfortunately, the energy consumption of tubular houses has not been investigated in previous research, and there remains a lack of experimental validation and quantitative analysis. Our group from Zhejiang University has studied tubular houses in northern Zhejiang Province for more than 10 years [32]. Active heating or cooling systems are generally in high demand for buildings in the northern Zhejiang Province due to the \"hot in summer and cool in winter\" climate of the region. Previous field measurements showed that there was much room for improvement with regard to thermal conditions in such dwellings, with both winter and summer cases requiring particular attention. Analyses of energy consumption and energy-saving potential based on field measurements and computer simulations for dwellings have been widely applied worldwide [25]. In this study, numerical simulations of the annual energy consumption were conducted using the tubular house model in Open  
Figure 1: (a,c) Appearance of the traditional tubular houses; (b) a base case in a group arrangement of tubular houses; (d,e) Google map of the tubular houses (2021). Studio. Different energy efficiency measures were evaluated in terms of the decrease in the annual energy consumption. Subsequently, the results show that various levels of reduction in energy consumption (varying from 1.6% to 30.5%) were achieved by combining different renovations. Furthermore, the relationship between energy consumption and insulation material thickness was established using a highly fitting logarithmic curve. To facilitate the understanding of the research method framework, it is presented in Figure 2.  
Step 1. Field Measurement: A series of experimental measurements were carried out, focusing on the characteristics of the tubular house and the current situation of the thermal comfort, to provide the basis for the study. Step 2. Investigation: The field investigation about modeling parameters of tubular house and a questionnaire survey about living schedule of 121 households were conducted. Step 3. Models Built: A typical tubular house was built in Open-Studio as CASE-A according to the parameters in steps 1 and 2. Step 4. Simulation: Several energy consumption simulations were conducted throughout the winter and summer by combining different renovations to solve the problems found in steps 1 and 2. Step 5. Analysis: Analyze all the simulation results, taking CASE-X as the integrated optimization measure, with an energy-saving rate of 47.4%. Step 6.