i-Yard 2.0: Integration of Sustainability into a Net-Zero Energy House
Round 1
Reviewer 1 Report
It would be good to provide some information about the construction and electromechanical equipment costs compared to a usual new building of this type.
Author Response
Point 1: It would be good to provide some information about the construction and electromechanical equipment costs compared to a usual new building of this type.
Response 1: Thank you for your suggestions. It has provided some information about the construction and electromechanical equipment costs in the two part of the article.
First part is in the lines 106-108
“……The modular assembly strategy not only accelerates construction, but also reduces construction costs. For the i-Yard 2.0, the total construction cost was USD $218,700, less than the average cost of NAHB in 2013.……”
Second part is in the line 222-225
“……In order to improve energy use and the built environment, the i-Yard 2.0 adopted a series of active and passive strategies such as solar panels and a geothermal system. The end result was that the i-Yard 2.0 achieved net-zero energy consumption for an electromechanical equipment cost of USD $30,300. This was higher than the average cost of NAHB in 2013.……”
(author also has uploaded an attachment of notes)
Author Response File: 
Author Response.docx
Reviewer 2 Report
Paper deals with residential net-zero energy house named i-Yard 2.0 demonstration project, which was built by a team from Beijing Jiaotong University. The topic is interesting and paper is well prepared however I have some minor remarks for improvement: my first concern is literature review. The paper lacks comprehensive literature to form background for current study. The discussion section is necessary to compare results with other similar studies, to discuss limit and advantages of this demo. Conclusions are weak, the policy implications are necessary for market take up this house type. The limitations of this study should be formulated and future research guidelines to address these limitations need to be addressed.
Author Response
Point 1: My first concern is literature review. The paper lacks comprehensive literature to form background for current study. The discussion section is necessary to compare results with other similar studies, to discuss limit and advantages of this demo.
Response 1: thank you for your suggestions. It is really necessary to add some information in the literature review. So it has added and changed some sentences in lines 41-45, lines 46-52, lines 55-62 and lines 64-72.
In lines 41-45
“……. In terms of design, it is quite different from a passive house, low energy house, and the nearly zero energy houses that can be seen in green buildings. For example, the “zero house” is a nearly zero energy house built in the suburbs of Beijing in 2019 [8]. Research on energy-saving strategies and design methods used in passive houses was published by Kai Liu and other Chinese scholars in 2020 [9]. The i-Yard 2.0 is a net--zero energy house that achieves energy self-sufficiency via solar energy……”
In lines 46-52
“……. The net-zero energy house uses renewable energy to completely supply the annual energy consumption of the building via a variety of active and passive designs and efficient energy savings equipment [11]. For example, the Aldo Leopold heritage center, built in the United States, realized net-zero energy consumption through a comprehensive strategic design [12]. A net-zero energy house can not only maximize energy consumption throughout the lifecycle of the building and achieve complete energy self-sufficiency, but also indirectly improve the ecological environment.……”
In lines 55-62
“……This was not a study of the net-zero energy design as applied to a type architecture, such as the 2020 work by Yu Zhang and other Chinese scholars who studied the development of an American net-zero energy structure that took the form of an education building [14]. Nor was it similar to the 2019 work by Jie Cheng and other Chinese scholars who studied the technology of net-zero energy houses in hot summer and cold winter regions [15]. Rather, the present work was based on China's increasingly acute population aging problem, and thus targeted a net-zero energy design for senior residential housing. The i-Yard 2.0 is quite specific in its design, and thus not entirely suitable for all types of residential housing.…….”
In lines 64-72
“……. Industrial construction and modular assembly can greatly reduce the construction cycle of net-zero energy houses, but this type of structure requires more thermal insulation and treatments to guarantee air-tightness at the junctions of building modules. For example, in 2018, AiSheng Wei and other Chinese scholars studied the thermal insulation and air-tightness of the joints of net-zero energy houses [16]. A variety of modular space combinations can meet different individual needs, breaking the homogeneity of traditional net-zero energy residential building spaces. Intelligent design provides a superior solution strategy for senior occupants and comprehensively improves the daily user experience of the elderly.……”
Point 2:Conclusions are weak, the policy implications are necessary for market take up this house type. The limitations of this study should be formulated and future research guidelines to address these limitations need to be addressed.
Response 2: thank you for you suggestion. In order to enrich conclusions , it has added some information in lines 372-386.
“……Therefore，if society seeks to promote the development of net-zero energy houses in new town developments, the novel design framework of the i-Yard 2.0 offers the following benefits:
- The modular assembly and rapid construction can shorten the construction cycle, reducing the energy and materials consumed in the process.
- The reasonable passive building space design can improve the comfort level of the environment within the building space, indirectly reducing energy consumption.
- A dynamic balance between energy acquisition and consumption can be achieved by improving active energy acquisition through techniques such as solar energy.
- The smart building control can reduce energy waste by more rationally and effectively regulating the daily operation of the entire building system based on different times and use modes.
The relatively high building cost limits the generalization of the i-Yard 2.0. Modular assembly can minimize the construction cycle, but also inevitably increases the building cost. Therefore, future research will focus on how to achieve relatively appropriate cost control with different materials according to the economic capacities of different users.”
（author also has uploaded an attachmant of notes ）
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
The paper was improved based on my comments.The current version can be published. The comprehensive answers on my comments were also provided.
