Nanonetworks is a communication between nanodevices, called nanomachines. Nanomachines are very small devices at the range of 10-9 metre. Molecular communication is one of the types of nanonetworks in which nanomachines are able to sense, calculate, actuate and intercommunicate. Transmission, propagation and reception are the three main stages to provide information exchange between sender and receiver in Molecular communication. Diffusion based molecular communication, that is an essential type of molecular communication, relies on propagation of molecules between sender and receiver nodes through free diffusion. This paper investigates how harvesting nodes can degrade the signal strength of the receiver node in a confined space. The analytic expression of the received signal at the receiver node has been drawn; the effects of the increasing number of harvesting nodes and the harvesting rate have been discussed in this paper.